Portfolio management

Purchase and sale of fund shares

The minimum initial investment requirement for Class A and Class C shares is $1,000 ($250 for group investments), except that there is no minimum for certain group retirement plans; or certain fee-based or wrap accounts; or certain other eligible investment product platforms. The minimum initial investment requirement for Class I shares is $250,000, except that the fund may waive the minimum for any category of investors at the fund's sole discretion. There are no minimum initial investment requirements for Class R1, Class R2, Class R3, Class R4, or Class R5 shares. The minimum initial investment requirement for Class R6 shares is $1 million, except that there is no minimum for: qualified and nonqualified plan investors that do not require the fund or its affiliates to pay any type of administrative payment; certain eligible qualifying investment product platforms; Trustees; employees of the advisor or its affiliates; or members of the fund's portfolio management team. There are no subsequent minimum investment requirements for any of these share classes.

Class A, Class B, Class C, Class I and Class R6 shares may be redeemed on any business day by mail: John Hancock Signature Services, Inc., P.O. Box 55913, Boston, Massachusetts 02205-5913; or for most account types through our website: jhinvestments.com; or by telephone: 800-225-5291 (Class A, Class B, and Class C); 888-972-8696 (Class I and Class R6). Class R1, Class R2, Class R3, Class R4, and Class R5 shares may be redeemed on any business day by contacting your retirement plan administrator or recordkeeper.

Taxes

The fund's distributions are taxable, and will be taxed as ordinary income and/or capital gains, unless you are investing through a tax-deferred arrangement, such as a 401(k) plan or individual retirement account. Withdrawals from such tax-deferred arrangements may be subject to tax at a later date.

Payments to broker-dealers and other financial intermediaries

If you purchase the fund through a broker-dealer or other financial intermediary (such as a bank, registered investment advisor, financial planner, or retirement plan administrator), the fund and its related companies may pay the broker-dealer or other intermediary for the sale of fund shares and related services. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your salesperson to recommend the fund over another investment. These payments are not applicable to Class R6 shares. Ask your salesperson or visit your financial intermediary's website for more information.

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Principal investment strategies

The Board of Trustees can change the fund's strategy without shareholder approval.

Under normal market conditions, the fund invests primarily in the following types of securities: foreign government and corporate debt securities from developed and emerging markets, U.S. government and agency securities, and domestic high-yield bonds.

The fund may also invest in preferred securities and other types of debt securities.

Although the fund may invest up to 10% of its total assets in securities rated, at the time of purchase, as low as D (in default) by Standard & Poor's Ratings Services (S&P) or Moody's Investors Service, Inc. (Moody's) (or their unrated equivalents), it generally intends to keep its average credit quality in the investment-grade range (AAA to BBB). The fund's investment policies are based on credit ratings at the time of purchase. There is no limit on the fund's average maturity.

In managing the fund, the manager allocates assets among the three major types of securities based on analysis of economic factors, such as projected international interest-rate movements, industry cycles, and political trends. However, the manager may invest up to 100% of the fund's assets in any one sector. Within each type of security, the manager looks for investments that are appropriate for the overall fund in terms of yield, credit quality, structure, and industry distribution. In selecting securities, relative yields and risk/reward ratios are the primary considerations.

The fund may use certain higher-risk investments, including restricted or illiquid securities and derivatives, which include futures contracts on securities, indexes, and foreign currency; options on futures contracts, securities, indexes, and foreign currency; interest-rate, foreign currency, and credit default swaps; and foreign currency forward contracts, in each case for the purposes of reducing risk, obtaining efficient market exposure, and/or enhancing investment returns. In addition, the fund may invest up to 10% of its net assets in domestic or foreign common stocks.

The fund may trade securities actively, which could increase its transaction costs (thus lowering performance) and increase your taxable distributions.

The fund may temporarily invest its assets in cash or investment-grade short-term securities for the purpose of meeting redemption requests or making other anticipated cash payments.

Temporary defensive investing

In abnormal circumstances, the fund may temporarily invest its assets extensively in cash or investment-grade short-term securities for the purpose of protecting the fund in the event the manager determines that market, economic, political, or other conditions warrant a defensive posture.

To the extent that the fund is in a defensive position, its ability to achieve its investment objective will be limited.

Principal risks of investing

An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The fund's shares will go up and down in price, meaning that you could lose money by investing in the fund. Many factors influence a mutual fund's performance. The fund's investment strategy may not produce the intended results.

Instability in the financial markets has led many governments, including the U.S. government, to take a number of unprecedented actions designed to support certain financial institutions and segments of the financial markets that have experienced extreme volatility and, in some cases, a lack of liquidity. Federal, state, and other governments, and their regulatory agencies or self-regulatory organizations, may take actions that affect the regulation of the instruments in which the fund invests, or the issuers of such instruments, in ways that are unforeseeable. Legislation or regulation may also change the way in which the fund itself is regulated. Such legislation or regulation could limit or preclude the fund's ability to achieve its investment objective. In addition, political events within the United States and abroad, could negatively impact financial markets and the fund's performance. Further, certain municipalities of the United States and its territories are financially strained and may face the possibility of default on their debt obligations, which could directly or indirectly detract from the fund's performance.

Governments or their agencies may also acquire distressed assets from financial institutions and acquire ownership interests in those institutions. The implications of government ownership and disposition of these assets are unclear, and such a program may have positive or negative effects on the liquidity, valuation, and performance of the fund's portfolio holdings. Furthermore, volatile financial markets can expose the fund to greater market and liquidity risk and potential difficulty in valuing portfolio instruments held by the fund.

Below are descriptions of the main factors that may play a role in shaping the fund's overall risk profile. The descriptions appear in alphabetical order, not in order of importance. For further details about fund risks, including additional risk factors that are not discussed in this prospectus because they are not considered primary factors, see the fund's Statement of Additional Information (SAI).

Changing distribution levels risk

The distribution amounts paid by the fund generally depend on the amount of income and/or dividends paid by the fund's investments. As a result of market, interest rate and other circumstances, the amount of cash available for distribution by the fund and the fund's distribution rate may vary or decline. The risk of such variability is accentuated in currently prevailing market and interest rate circumstances.

Credit and counterparty risk

This is the risk that the issuer or guarantor of a fixed-income security, the counterparty to an over-the-counter (OTC) derivatives contract (see "Hedging, derivatives, and other strategic transactions risk"), or a borrower of a fund's securities will be unable or unwilling to make timely principal, interest, or settlement payments, or otherwise honor its obligations. Credit risk associated with investments in fixed-income securities relates to the ability of the issuer to make scheduled payments of principal and interest on an obligation. A fund that invests in fixed-income securities is subject to varying degrees of risk that the issuers of the securities will have their credit ratings downgraded or will default, potentially reducing the fund's share price and income level. Nearly all fixed-income securities are subject to some credit risk, which may vary depending upon whether the issuers of the securities are corporations, domestic or foreign governments, or their subdivisions or instrumentalities. U.S. government securities are subject to varying degrees of credit risk depending

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upon whether the securities are supported by the full faith and credit of the United States; the ability to borrow from the U.S. Treasury; only by the credit of the issuing U.S. government agency, instrumentality, or corporation; or otherwise supported by the United States. For example, issuers of many types of U.S. government securities (e.g., the Federal Home Loan Mortgage Corporation (Freddie Mac), Federal National Mortgage Association (Fannie Mae), and Federal Home Loan Banks), although chartered or sponsored by Congress, are not funded by congressional appropriations, and their fixed-income securities, including asset-backed and mortgage-backed securities, are neither guaranteed nor insured by the U.S. government. An agency of the U.S. government has placed Fannie Mae and Freddie Mac into conservatorship, a statutory process with the objective of returning the entities to normal business operations. It is unclear what effect this conservatorship will have on the securities issued or guaranteed by Fannie Mae or Freddie Mac. As a result, these securities are subject to more credit risk than U.S. government securities that are supported by the full faith and credit of the United States (e.g., U.S. Treasury bonds). When a fixed-income security is not rated, a manager may have to assess the risk of the security itself. Asset-backed securities, whose principal and interest payments are supported by pools of other assets, such as credit card receivables and automobile loans, are subject to further risks, including the risk that the obligors of the underlying assets default on payment of those assets.

Funds that invest in below-investment-grade securities, also called junk bonds (e.g., fixed-income securities rated Ba or lower by Moody's Investors Service, Inc. or BB or lower by Standard & Poor's Ratings Services, at the time of investment, or determined by a manager to be of comparable quality to securities so rated) are subject to increased credit risk. The sovereign debt of many foreign governments, including their subdivisions and instrumentalities, falls into this category. Below-investment-grade securities offer the potential for higher investment returns than higher-rated securities, but they carry greater credit risk: their issuers' continuing ability to meet principal and interest payments is considered speculative, they are more susceptible to real or perceived adverse economic and competitive industry conditions, and they may be less liquid than higher-rated securities.

In addition, a fund is exposed to credit risk to the extent that it makes use of OTC derivatives (such as forward foreign currency contracts and/or swap contracts) and engages to a significant extent in the lending of fund securities or the use of repurchase agreements. OTC derivatives transactions can be closed out with the other party to the transaction. If the counterparty defaults, a fund will have contractual remedies, but there is no assurance that the counterparty will be able to meet its contractual obligations or that, in the event of default, a fund will succeed in enforcing them. A fund, therefore, assumes the risk that it may be unable to obtain payments owed to it under OTC derivatives contracts or that those payments may be delayed or made only after the fund has incurred the costs of litigation. While the manager intends to monitor the creditworthiness of contract counterparties, there can be no assurance that the counterparty will be in a position to meet its obligations, especially during unusually adverse market conditions.

Cybersecurity and operational risk

Intentional cybersecurity breaches include unauthorized access to systems, networks, or devices (such as through "hacking" activity); infection from computer viruses or other malicious software code; and attacks that shut down, disable, slow, or otherwise disrupt operations, business processes, or website access or functionality. In addition, unintentional incidents can occur, such as the inadvertent release of confidential information (possibly resulting in the violation of applicable privacy laws).

A cybersecurity breach could result in the loss or theft of customer data or funds, the inability to access electronic systems ("denial of services"), loss or theft of proprietary information or corporate data, physical damage to a computer or network system, or costs associated with system repairs. Such incidents could cause a fund, the advisor, a manager, or other service providers to incur regulatory penalties, reputational damage, additional compliance costs, or financial loss. In addition, such incidents could affect issuers in which a fund invests, and thereby cause the fund's investments to lose value.

The fund is exposed to operational risk arising from a number of factors, including, but not limited to, human error, processing and communication errors, errors of the fund's service providers, counterparties, or other third parties, failed or inadequate processes and technology or system failures.

Defaulted debt risk

Investing in defaulted debt securities is speculative and involves substantial risks in addition to the risks of investing in high-yield securities that have not defaulted. The fund generally will not receive interest payments on defaulted debt securities, and there is a substantial risk that principal will not be repaid. A fund investing in defaulted debt securities may incur additional expenses to the extent that it is required to seek recovery upon a default in the payment of principal of or interest on the securities. In any reorganization or liquidation proceeding relating to defaulted debt, a fund may lose its entire investment in such securities or may be required to accept cash or securities with a value lower than the fund's original investment. Defaulted debt securities and any securities received in exchange for defaulted debt securities may be subject to restrictions on resale.

Economic and market events risk

Events in certain sectors historically have resulted, and may in the future result, in an unusually high degree of volatility in the financial markets, both domestic and foreign. These events have included, but are not limited to: bankruptcies, corporate restructurings, and other events related to the sub-prime mortgage crisis in 2008; governmental efforts to limit short selling and high frequency trading; measures to address U.S. federal and state budget deficits; social, political, and economic instability in Europe; economic stimulus by the Japanese central bank; steep declines in oil prices; dramatic changes in currency exchange rates; and China's economic slowdown. Interconnected global economies and financial markets increase the possibility that conditions in one country or region might adversely impact issuers in a different country or region. Both domestic and foreign equity markets have experienced increased volatility and turmoil, with issuers that have exposure to the real estate, mortgage, and credit markets particularly affected. Banks and financial services companies could suffer losses if interest rates continue to rise or economic conditions deteriorate.

In addition, relatively high market volatility and reduced liquidity in credit and fixed-income markets may adversely affect many issuers worldwide. Actions taken by the U.S. Federal Reserve (Fed) or foreign central banks to stimulate or stabilize economic growth, such as interventions in currency markets, could cause high volatility in the equity and fixed-income markets. Reduced liquidity may result in less money being available to purchase raw materials, goods, and services from emerging markets, which may, in turn, bring down the prices of these economic staples. It may also result in emerging-market issuers having

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more difficulty obtaining financing, which may, in turn, cause a decline in their securities prices.

In addition, while interest rates have been unusually low in recent years in the United States and abroad, the Fed's decision to raise the target fed funds rate in 2017, following a similar move the previous year, and the possibility that the Fed may continue with such rate increases, among other factors, could cause markets to experience continuing high volatility. A significant increase in interest rates may cause a decline in the market for equity securities. Also, regulators have expressed concern that rate increases may contribute to price volatility. These events and the possible resulting market volatility may have an adverse effect on the fund.

Political turmoil within the United States and abroad may also impact the fund. Although the U.S. government has honored its credit obligations, it remains possible that the United States could default on its obligations. While it is impossible to predict the consequences of such an unprecedented event, it is likely that a default by the United States would be highly disruptive to the U.S. and global securities markets and could significantly impair the value of the fund's investments. Similarly, political events within the United States at times have resulted, and may in the future result, in a shutdown of government services, which could negatively affect the U.S. economy, decrease the value of many fund investments, and increase uncertainty in or impair the operation of the U.S. or other securities markets. The U.S. is also considering significant new investments in infrastructure and national defense which, coupled with the prospect of lower federal taxes, could lead to increased government borrowing and higher interest rates. While these proposed policies are going through the political process, the equity and debt markets may react strongly to expectations, which could increase volatility, especially if the market's expectations for changes in government policies are not borne out.

Uncertainties surrounding the sovereign debt of a number of European Union (EU) countries and the viability of the EU have disrupted and may in the future disrupt markets in the United States and around the world. If one or more countries leave the EU or the EU dissolves, the world's securities markets likely will be significantly disrupted. In June 2016, the United Kingdom approved a referendum to leave the EU, commonly referred to as "Brexit." There is significant market uncertainty regarding Brexit's ramifications, and the range and potential implications of possible political, regulatory, economic, and market outcomes are difficult to predict. Political and military events, including in North Korea, Syria and other areas of the Middle East, Venezuela, and nationalist unrest in Europe, also may cause market disruptions.

In addition, there is a risk that the prices of goods and services in the United States and many foreign economies may decline over time, known as deflation. Deflation may have an adverse effect on stock prices and creditworthiness and may make defaults on debt more likely. If a country's economy slips into a deflationary pattern, it could last for a prolonged period and may be difficult to reverse.

Equity securities risk

Common and preferred stocks represent equity ownership in a company. Stock markets are volatile. The price of equity securities will fluctuate, and can decline and reduce the value of a fund investing in equities. The price of equity securities fluctuates based on changes in a company's financial condition and overall market and economic conditions. The value of equity securities purchased by a fund could decline if the financial condition of the companies in which the fund is invested declines, or if overall market and economic conditions deteriorate. An issuer's financial condition could decline as a result of poor management decisions, competitive pressures, technological obsolescence, undue reliance on suppliers, labor issues, shortages, corporate restructurings, fraudulent disclosures, or other factors. Changes in the financial condition of a single issuer can impact the market as a whole.

Even a fund that invests in high-quality, or blue chip, equity securities, or securities of established companies with large market capitalizations (which generally have strong financial characteristics), can be negatively impacted by poor overall market and economic conditions. Companies with large market capitalizations may also have less growth potential than smaller companies and may be less able to react quickly to changes in the marketplace.

The fund may maintain substantial exposure to equities and generally does not attempt to time the market. Because of this exposure, the possibility that stock market prices in general will decline over short or extended periods subjects the fund to unpredictable declines in the value of its investments, as well as periods of poor performance.

Fixed-income securities risk

Fixed-income securities are generally subject to two principal types of risk, as well as other risks described below: (1) interest-rate risk and (2) credit quality risk.

Interest-rate risk. Fixed-income securities are affected by changes in interest rates. When interest rates decline, the market value of fixed-income securities generally can be expected to rise. Conversely, when interest rates rise, the market value of fixed-income securities generally can be expected to decline. The longer the duration or maturity of a fixed-income security, the more susceptible it is to interest-rate risk. Recent and potential future changes in government monetary policy may affect the level of interest rates.

Credit quality risk. Fixed-income securities are subject to the risk that the issuer of the security will not repay all or a portion of the principal borrowed and will not make all interest payments. If the credit quality of a fixed-income security deteriorates after a fund has purchased the security, the market value of the security may decrease and lead to a decrease in the value of the fund's investments. An issuer's credit quality could deteriorate as a result of poor management decisions, competitive pressures, technological obsolescence, undue reliance on suppliers, labor issues, shortages, corporate restructurings, fraudulent disclosures, or other factors. Funds that may invest in lower-rated fixed-income securities, commonly referred to as junk securities, are riskier than funds that may invest in higher-rated fixed-income securities. Additional information on the risks of investing in investment-grade fixed-income securities in the lowest rating category and lower-rated fixed-income securities is set forth below.

Investment-grade fixed-income securities in the lowest rating category risk. Investment-grade fixed-income securities in the lowest rating category (such as Baa by Moody's Investors Service, Inc. or BBB by Standard & Poor's Ratings Services and comparable unrated securities) involve a higher degree of risk than fixed-income securities in the higher rating categories. While such securities are considered investment-grade quality and are deemed to have adequate capacity for payment of principal and interest, such securities lack outstanding investment characteristics and have speculative characteristics as well. For example, changes in economic conditions or other circumstances are more likely to lead to a weakened

Prepayment of principal risk. Many types of debt securities, including floating-rate loans, are subject to prepayment risk. Prepayment risk occurs when the issuer of a security can repay principal prior to the security's maturity. Securities subject to prepayment risk can offer less potential for gains when the credit quality of the issuer improves.

Foreign securities risk

Funds that invest in securities traded principally in securities markets outside the United States are subject to additional and more varied risks, as the value of foreign securities may change more rapidly and extremely than the value of U.S. securities. The securities markets of many foreign countries are relatively small, with a limited number of companies representing a small number of industries. Additionally, issuers of foreign securities may not be subject to the same degree of regulation as U.S. issuers. Reporting, accounting, and auditing standards of foreign countries differ, in some cases significantly, from U.S. standards. There are generally higher commission rates on foreign portfolio transactions, transfer taxes, higher custodial costs, and the possibility that foreign taxes will be charged on dividends and interest payable on foreign securities, some or all of which may not be reclaimable. Also, for lesser-developed countries, nationalization, expropriation, or confiscatory taxation; adverse changes in investment or exchange control regulations (which may include suspension of the ability to transfer currency or assets from a country); political changes; or diplomatic developments could adversely affect a fund's investments. In the event of nationalization, expropriation, or other confiscation, the fund could lose its entire investment in a foreign security. All funds that invest in foreign securities are subject to these risks. Some of the foreign risks are also applicable to funds that invest a material portion of their assets in securities of foreign issuers traded in the United States.

Emerging-market risk. Investments in the securities of issuers based in countries with emerging-market economies are subject to greater levels of foreign investment risk than investments in more-developed foreign markets, since emerging-market securities may present market, credit, currency, liquidity, legal, political, and other risks greater than, or in addition to, the risks of investing in developed foreign countries. These risks include high currency exchange-rate fluctuations; increased risk of default (including both government and private issuers); greater social, economic, and political uncertainty and instability (including the risk of war); more substantial governmental involvement in the economy; less governmental supervision and regulation of the securities markets and participants in those markets; controls on foreign investment and limitations on repatriation of invested capital and on a fund's ability to exchange local currencies for U.S. dollars; unavailability of currency hedging techniques in certain emerging-market countries; the fact that companies in emerging-market countries may be newly organized, smaller, and less seasoned; the difference in, or lack of, auditing and financial reporting standards, which may result in the unavailability of material information about issuers; different clearance and settlement procedures, which may be unable to keep pace with the volume of securities transactions or otherwise make it difficult to engage in such transactions; difficulties in obtaining and/or enforcing legal judgments in foreign jurisdictions; and significantly smaller market capitalizations of emerging-market issuers.

Currency risk. Currency risk is the risk that fluctuations in exchange rates may adversely affect the U.S. dollar value of a fund's investments. Currency risk includes both the risk that currencies in which a fund's investments are traded, or currencies in which a fund has taken an active investment position, will decline in value relative to the U.S. dollar and, in the case of hedging positions, that the U.S. dollar will decline in value relative to the currency being hedged. Currency rates in foreign countries may fluctuate significantly for a number of reasons, including the forces of supply and demand in the foreign exchange markets, actual or perceived changes in interest rates, and intervention (or the failure to intervene) by U.S. or foreign governments or central banks, or by currency controls or political developments in the United States or abroad. Certain funds may engage in proxy hedging of currencies by entering into derivative transactions with respect to a currency whose value is expected to correlate to the value of a currency the fund owns or wants to own. This presents the risk that the two currencies may not move in relation to one another as expected. In that case, the fund could lose money on its investment and also lose money on the position designed to act as a proxy hedge. Certain funds may also take active currency positions and may cross-hedge currency exposure represented by their securities into another foreign currency. This may result in a fund's currency exposure being substantially different from that suggested by its securities investments. All funds with foreign currency holdings and/or that invest or trade in securities denominated in foreign currencies or related derivative instruments may be adversely affected by changes in foreign currency exchange rates. Derivative foreign currency transactions (such as futures, forwards, and swaps) may also involve leveraging risk, in addition to currency risk. Leverage may disproportionately increase a fund's portfolio losses and reduce opportunities for gain when interest rates, stock prices, or currency rates are changing.

Hedging, derivatives, and other strategic transactions risk

The ability of a fund to utilize hedging, derivatives, and other strategic transactions to benefit the fund will depend in part on its manager's ability to predict pertinent market movements and market risk, counterparty risk, credit risk, interest-rate risk, and other risk factors, none of which can be assured. The skills required to utilize hedging and other strategic transactions are different from those needed to select a fund's securities. Even if the manager only uses hedging and other strategic transactions in a fund primarily for hedging purposes or to gain exposure to a particular securities market, if the transaction does not have the desired outcome, it could result in a significant loss to a fund. The amount of loss could be more than the principal amount invested. These transactions may also increase the volatility of a fund and may involve a small investment of cash relative to the magnitude of the risks assumed, thereby magnifying the impact of any resulting gain or loss. For example, the potential loss from the use of futures can exceed a fund's initial investment in such contracts. In addition, these transactions could result in a loss to a fund if the counterparty to the transaction does not perform as promised.

A fund may invest in derivatives, which are financial contracts with a value that depends on, or is derived from, the value of underlying assets, reference rates, or indexes. Derivatives may relate to stocks, bonds, interest rates, currencies or currency exchange rates, and related indexes. A fund may use derivatives for many purposes, including for hedging and as a substitute for direct investment in securities or other assets. Derivatives may be used in a way to efficiently adjust the exposure of a fund to various securities, markets, and currencies without a fund actually having to sell existing investments and make new investments. This generally will be done when the adjustment is expected to be relatively temporary or in anticipation of effecting the sale of fund assets and making new investments over time. Further, since many derivatives have a

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leverage component, adverse changes in the value or level of the underlying asset, reference rate, or index can result in a loss substantially greater than the amount invested in the derivative itself. Certain derivatives have the potential for unlimited loss, regardless of the size of the initial investment. When a fund uses derivatives for leverage, investments in that fund will tend to be more volatile, resulting in larger gains or losses in response to market changes. To limit leverage risk, a fund may segregate assets determined to be liquid or, as permitted by applicable regulation, enter into certain offsetting positions to cover its obligations under derivative instruments. For a description of the various derivative instruments the fund may utilize, refer to the SAI.

The regulation of the U.S. and non-U.S. derivatives markets has undergone substantial change in recent years and such change may continue. In particular, the Dodd-Frank Wall Street Reform and Consumer Protection Act, and regulation proposed to be promulgated thereunder require many derivatives to be cleared and traded on an exchange, expand entity registration requirements, impose business conduct requirements on dealers that enter into swaps with a pension plan, endowment, retirement plan or government entity, and required banks to move some derivatives trading units to a non-guaranteed affiliate separate from the deposit-taking bank or divest them altogether. Although the Commodity Futures Trading Commission (CFTC) has released final rules relating to clearing, reporting, recordkeeping and registration requirements under the legislation, many of the provisions are subject to further final rule making, and thus its ultimate impact remains unclear. New regulations could, among other things, restrict the fund's ability to engage in derivatives transactions (for example, by making certain types of derivatives transactions no longer available to the fund) and/or increase the costs of such derivatives transactions (for example, by increasing margin or capital requirements), and the fund may be unable to fully execute its investment strategies as a result. Limits or restrictions applicable to the counterparties with which the fund engages in derivative transactions also could prevent the fund from using these instruments or affect the pricing or other factors relating to these instruments, or may change the availability of certain investments.

At any time after the date of this prospectus, legislation may be enacted that could negatively affect the assets of the fund. Legislation or regulation may change the way in which the fund itself is regulated. The advisor cannot predict the effects of any new governmental regulation that may be implemented, and there can be no assurance that any new governmental regulation will not adversely affect the fund's ability to achieve its investment objectives.

The use of derivative instruments may involve risks different from, or potentially greater than, the risks associated with investing directly in securities and other, more traditional assets. In particular, the use of derivative instruments exposes a fund to the risk that the counterparty to an OTC derivatives contract will be unable or unwilling to make timely settlement payments or otherwise honor its obligations. OTC derivatives transactions typically can only be closed out with the other party to the transaction, although either party may engage in an offsetting transaction that puts that party in the same economic position as if it had closed out the transaction with the counterparty or may obtain the other party's consent to assign the transaction to a third party. If the counterparty defaults, the fund will have contractual remedies, but there is no assurance that the counterparty will meet its contractual obligations or that, in the event of default, the fund will succeed in enforcing them. For example, because the contract for each OTC derivatives transaction is individually negotiated with a specific counterparty, a fund is subject to the risk that a counterparty may interpret contractual terms (e.g., the definition of default) differently than the fund when the fund seeks to enforce its contractual rights. If that occurs, the cost and unpredictability of the legal proceedings required for the fund to enforce its contractual rights may lead it to decide not to pursue its claims against the counterparty. The fund, therefore, assumes the risk that it may be unable to obtain payments owed to it under OTC derivatives contracts or that those payments may be delayed or made only after the fund has incurred the costs of litigation. While a manager intends to monitor the creditworthiness of counterparties, there can be no assurance that a counterparty will meet its obligations, especially during unusually adverse market conditions. To the extent a fund contracts with a limited number of counterparties, the fund's risk will be concentrated and events that affect the creditworthiness of any of those counterparties may have a pronounced effect on the fund. Derivatives are also subject to a number of other risks, including market risk and liquidity risk. Since the value of derivatives is calculated and derived from the value of other assets, instruments, or references, there is a risk that they will be improperly valued. Derivatives also involve the risk that changes in their value may not correlate perfectly with the assets, rates, or indexes they are designed to hedge or closely track. Suitable derivatives transactions may not be available in all circumstances. The fund is also subject to the risk that the counterparty closes out the derivatives transactions upon the occurrence of certain triggering events. In addition, a manager may determine not to use derivatives to hedge or otherwise reduce risk exposure. Government legislation or regulation could affect the use of derivatives transactions and could limit a fund's ability to pursue its investment strategies.

A detailed discussion of various hedging and other strategic transactions appears in the SAI. The following is a list of certain derivatives and other strategic transactions that the fund may utilize and the main risks associated with each of them:

Credit default swaps. Counterparty risk, liquidity risk (i.e., the inability to enter into closing transactions), interest-rate risk, risk of default of the underlying reference obligation, and risk of disproportionate loss are the principal risks of engaging in transactions involving credit default swaps.

Foreign currency forward contracts. Counterparty risk, liquidity risk (i.e., the inability to enter into closing transactions), foreign currency risk, and risk of disproportionate loss are the principal risks of engaging in transactions involving foreign currency forward contracts.

Foreign currency swaps. Counterparty risk, liquidity risk (i.e., the inability to enter into closing transactions), foreign currency risk, and risk of disproportionate loss are the principal risks of engaging in transactions involving foreign currency swaps.

Futures contracts. Counterparty risk, liquidity risk (i.e., the inability to enter into closing transactions), and risk of disproportionate loss are the principal risks of engaging in transactions involving futures contracts.

Interest-rate swaps. Counterparty risk, liquidity risk (i.e., the inability to enter into closing transactions), interest-rate risk, and risk of disproportionate loss are the principal risks of engaging in transactions involving interest-rate swaps.

Options. Counterparty risk, liquidity risk (i.e., the inability to enter into closing transactions), and risk of disproportionate loss are the principal risks of engaging in transactions involving options. Counterparty risk does not apply to exchange-traded options.

High portfolio turnover risk

A high fund portfolio turnover rate (over 100%) generally involves correspondingly greater brokerage commission and tax expenses, which must be borne directly by a fund and its shareholders, respectively. The portfolio turnover rate of a fund may vary from year to year, as well as within a year.

Liquidity risk

The extent (if at all) to which a security may be sold or a derivative position closed without negatively impacting its market value may be impaired by reduced market activity or participation, legal restrictions, or other economic and market impediments. Funds with principal investment strategies that involve investments in securities of companies with smaller market capitalizations, foreign securities, derivatives, or securities with substantial market and/or credit risk tend to have the greatest exposure to liquidity risk. Exposure to liquidity risk may be heightened for funds that invest in securities of emerging markets and related derivatives that are not widely traded, and that may be subject to purchase and sale restrictions.

The capacity of traditional dealers to engage in fixed-income trading has not kept pace with the bond market's growth. As a result, dealer inventories of corporate bonds, which indicate the ability to "make markets," i.e., buy or sell a security at the quoted bid and ask price, respectively, are at or near historic lows relative to market size. Because market makers provide stability to fixed-income markets, the significant reduction in dealer inventories could lead to decreased liquidity and increased volatility, which may become exacerbated during periods of economic or political stress.

Lower-rated and high-yield fixed-income securities risk

Lower-rated fixed-income securities are defined as securities rated below investment grade (such as Ba and below by Moody's Investors Service, Inc. and BB and below by Standard & Poor's Ratings Services) (also called junk bonds). The general risks of investing in these securities are as follows:

Risk to principal and income. Investing in lower-rated fixed-income securities is considered speculative. While these securities generally provide greater income potential than investments in higher-rated securities, there is a greater risk that principal and interest payments will not be made. Issuers of these securities may even go into default or become bankrupt.

Price volatility. The price of lower-rated fixed-income securities may be more volatile than securities in the higher-rated categories. This volatility may increase during periods of economic uncertainty or change. The price of these securities is affected more than higher-rated fixed-income securities by the market's perception of their credit quality, especially during times of adverse publicity. In the past, economic downturns or increases in interest rates have, at times, caused more defaults by issuers of these securities and may do so in the future. Economic downturns and increases in interest rates have an even greater effect on highly leveraged issuers of these securities.

Liquidity. The market for lower-rated fixed-income securities may have more limited trading than the market for investment-grade fixed-income securities. Therefore, it may be more difficult to sell these securities, and these securities may have to be sold at prices below their market value in order to meet redemption requests or to respond to changes in market conditions.

Dependence on manager's own credit analysis. While a manager may rely on ratings by established credit rating agencies, it will also supplement such ratings with its own independent review of the credit quality of the issuer. Therefore, the assessment of the credit risk of lower-rated fixed-income securities is more dependent on the manager's evaluation than the assessment of the credit risk of higher-rated securities.

Additional risks regarding lower-rated corporate fixed-income securities. Lower-rated corporate fixed-income securities (and comparable unrated securities) tend to be more sensitive to individual corporate developments and changes in economic conditions than higher-rated corporate fixed-income securities. Issuers of lower-rated corporate fixed-income securities may also be highly leveraged, increasing the risk that principal and income will not be repaid.

Additional risks regarding lower-rated foreign government fixed-income securities. Lower-rated foreign government fixed-income securities are subject to the risks of investing in foreign countries described under "Foreign securities risk." In addition, the ability and willingness of a foreign government to make payments on debt when due may be affected by the prevailing economic and political conditions within the country. Emerging-market countries may experience high inflation, interest rates, and unemployment, as well as exchange-rate fluctuations which adversely affect trade and political uncertainty or instability. These factors increase the risk that a foreign government will not make payments when due.

Preferred and convertible securities risk

Unlike interest on debt securities, preferred stock dividends are payable only if declared by the issuer's board. Also, preferred stock may be subject to optional or mandatory redemption provisions. The market values of convertible securities tend to fall as interest rates rise and rise as interest rates fall. The value of convertible preferred stock can depend heavily upon the value of the security into which such convertible preferred stock is converted, depending on whether the market price of the underlying security exceeds the conversion price.

Sector risk

When a fund's investments are focused in one or a few sectors of the economy, they are not as diversified as the investments of most funds and are far less diversified than the broad securities markets. This means that focused funds tend to be more volatile than other funds, and the values of their investments tend to go up and down more rapidly. In addition, a fund which invests in particular sectors is particularly susceptible to the impact of market, economic, regulatory, and other factors affecting those sectors.  From time to time, a small number of companies may represent a large portion of a particular sector or sectors.

Who's who

The following are the names of the various entities involved with the fund's investment and business operations, along with brief descriptions of the role each entity performs.

Board of Trustees

The trustees oversee the fund's business activities and retain the services of the various firms that carry out the fund's operations.

Investment advisor

The investment advisor manages the fund's business and investment activities.

John Hancock Advisers, LLC
601 Congress Street
Boston, MA 02210-2805

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Founded in 1968, the advisor is a wholly owned subsidiary of John Hancock Life Insurance Company (U.S.A.), which in turn is a subsidiary of Manulife Financial Corporation.

The advisor's parent company has been helping individuals and institutions work toward their financial goals since 1862. The advisor offers investment solutions managed by leading institutional money managers, taking a disciplined team approach to portfolio management and research, leveraging the expertise of seasoned investment professionals. As of June 30, 2017, the advisor had total assets under management of approximately $144.7 billion.

Subject to general oversight by the Board of Trustees, the advisor manages and supervises the investment operations and business affairs of the fund. The advisor selects, contracts with and compensates one or more subadvisors to manage all or a portion of the fund's portfolio assets, subject to oversight by the advisor. In this role, the advisor has supervisory responsibility for managing the investment and reinvestment of the fund's portfolio assets through proactive oversight and monitoring of the subadvisor and the fund, as described in further detail below. The advisor is responsible for developing overall investment strategies for the fund and overseeing and implementing the fund's continuous investment programs and provides a variety of advisory oversight and investment research services. The advisor also provides management and transition services associated with certain fund events (e.g., strategy, portfolio manager or subadvisor changes) and coordinates and oversees services provided under other agreements.

The advisor has ultimate responsibility to oversee a subadvisor and recommend to the Board of Trustees its hiring, termination, and replacement. In this capacity, the advisor, among other things: (i) monitors on a daily basis the compliance of the subadvisor with the investment objectives and related policies of the fund; (ii) monitors significant changes that may impact the subadvisor's overall business and regularly performs due diligence reviews of the subadvisor; (iii) reviews the performance of the subadvisor; and (iv) reports periodically on such performance to the Board of Trustees. The advisor employs a team of investment professionals who provide these ongoing research and monitoring services.

The fund relies on an order from the Securities and Exchange Commission (SEC) permitting the advisor, subject to approval by the Board of Trustees, to appoint a subadvisor or change the terms of a subadvisory agreement without obtaining shareholder approval. The fund, therefore, is able to change subadvisors or the fees paid to a subadvisor, from time to time, without the expense and delays associated with obtaining shareholder approval of the change. This order does not, however, permit the advisor to appoint a subadvisor that is an affiliate of the advisor or the fund (other than by reason of serving as a subadvisor to the fund), or to increase the subadvisory fee of an affiliated subadvisor, without the approval of the shareholders.

During its most recent fiscal year, the fund paid the advisor a management fee equal to 0.31% of average daily net assets (including any waivers and/or reimbursements).

The basis for the Board of Trustees' approval of the advisory fees, and of the investment advisory agreement overall, including the subadvisory agreement, is discussed in the fund's most recent semiannual shareholder report for the period ended November 30.

Additional information about fund expenses

The fund's annual operating expenses will likely vary throughout the period and from year to year. The fund's expenses for the current fiscal year may be higher than the expenses listed in the fund's Annual fund operating expenses table, for some of the following reasons: (i) a significant decrease in average net assets may result in a higher advisory fee rate if advisory fee breakpoints are not achieved; (ii) a significant decrease in average net assets may result in an increase in the expense ratio because certain fund expenses do not decrease as asset levels decrease; or (iii) fees may be incurred for extraordinary events such as fund tax expenses.

In addition to any expense waivers and/or reimbursement arrangements described in "Fund summary - Fees and expenses" on page 1 of this prospectus, the advisor has contractually agreed to waive a portion of its management fee and/or reimburse expenses for certain funds of the John Hancock funds complex, including the fund (the participating portfolios). The waiver equals, on an annualized basis, 0.0100% of that portion of the aggregate net assets of all the participating portfolios that exceeds $75 billion but is less than or equal to $125 billion; 0.0125% of that portion of the aggregate net assets of all the participating portfolios that exceeds $125 billion but is less than or equal to $150 billion; 0.0150% of that portion of the aggregate net assets of all the participating portfolios that exceeds $150 billion but is less than or equal to $175 billion; 0.0175% of that portion of the aggregate net assets of all the participating portfolios that exceeds $175 billion but is less than or equal to $200 billion; 0.0200% of that portion of the aggregate net assets of all the participating portfolios that exceeds $200 billion but is less than or equal to $225 billion; and 0.0225% of that portion of the aggregate net assets of all the participating portfolios that exceeds $225 billion. The amount of the reimbursement is calculated daily and allocated among all the participating portfolios in proportion to the daily net assets of each fund. This arrangement may be amended or terminated at any time by the advisor upon notice to the funds and with the approval of the Board of Trustees.

The advisor voluntarily agrees to reduce its management fee for the fund, or if necessary make payment to the fund, in an amount equal to the amount by which the expenses of the fund exceed 0.15% of the average net assets of the fund. For purposes of this agreement, "expenses of the fund" means all the expenses of the fund, excluding (a) taxes, (b) brokerage commissions, (c) interest expense, (d) litigation and indemnification expenses and other extraordinary expenses not incurred in the ordinary course of the fund's

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business, (e) advisory fees, (f) class-specific expenses, (g) borrowing costs, (h) prime brokerage fees, (i) acquired fund fees and expenses paid indirectly, and (j) short dividend expense. This agreement will continue in effect until terminated at any time by the advisor on notice to the fund.

Subadvisor

The subadvisor handles the fund's portfolio management activities, subject to oversight by the advisor.

John Hancock Asset Management a division of Manulife Asset Management (US) LLC
197 Clarendon Street
Boston, MA 02116

John Hancock Asset Management a division of Manulife Asset Management (US) LLC provides investment advisory services to individual and institutional investors. John Hancock Asset Management a division of Manulife Asset Management (US) LLC is a wholly owned subsidiary of John Hancock Life Insurance Company (U.S.A.) (a subsidiary of Manulife Financial Corporation) and, as of June 30, 2017, had total assets under management of approximately $199.8 billion.

Following are brief biographical profiles of the leaders of the fund's investment management team in alphabetical order. These managers are jointly and primarily responsible for the day-to-day management of the fund's portfolio. For more about these individuals, including information about their compensation, other accounts they manage, and any investments they may have in the fund, see the SAI.

Chistopher M. Chapman, CFA

Managing Director and Portfolio Manager

Managed the fund since 2017

Primarily responsible for fund management and research of global sovereign debt and currencies

Joined subadvisor in 2005

Began business career in 1999

Thomas C. Goggins

Senior Managing Director and Senior Portfolio Manager

Managed the fund since 2009

Co-Founder and Director of Research, Fontana Capital (2005–2009)

Primarily responsible for portfolio management, asset allocation, and capital structure research

Began business career in 1989

Daniel S. Janis III

Senior Managing Director and Senior Portfolio Manager

Managed the fund since 1999

Primarily responsible for fund management and day-to-day purchase and sale decisions

Began business career in 1984

Kisoo Park

Managing Director and Portfolio Manager

Managed the fund since 2015

Primarily responsible for fund management and research of global bonds and currencies

Joined subadvisor in 2011

Custodian

The custodian holds the fund's assets, settles all portfolio trades, and collects most of the valuation data required for calculating the fund's net asset value.

State Street Bank and Trust Company
State Street Financial Center
One Lincoln Street
Boston, MA 02111

Principal distributor

The principal distributor markets the fund and distributes shares through selling brokers, financial planners, and other financial representatives.

John Hancock Funds, LLC
601 Congress Street
Boston, MA 02210-2805

Transfer agent

The transfer agent handles shareholder services, including recordkeeping and statements, distribution of dividends, and processing of buy-and-sell requests.

John Hancock Signature Services, Inc.
P.O. Box 55913
Boston, MA 02205-5913

Additional information

The fund has entered into contractual arrangements with various parties that provide services to the fund, which may include, among others, the advisor, subadvisor, custodian, principal distributor, and transfer agent, as described above and in the SAI. Fund shareholders are not parties to, or intended or "third-party" beneficiaries of, any of these contractual arrangements. These contractual arrangements are not intended to, nor do they, create in any individual shareholder or group of shareholders any right, either directly or on behalf of the fund, to either: (a) enforce such contracts against the service providers; or (b) seek any remedy under such contracts against the service providers.

This prospectus provides information concerning the fund that you should consider in determining whether to purchase shares of the fund. Each of this prospectus, the SAI, or any contract that is an exhibit to the fund's registration statement, is not intended to, nor does it, give rise to an agreement or contract between the fund and any investor. Each such document also does not give rise to any contract or create rights in any individual shareholder, group of shareholders, or other person. The foregoing disclosure should not be read to suggest any waiver of any rights conferred by federal or state securities laws.

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Financial highlights

These tables detail the financial performance of each share class described in this prospectus, including total return information showing how much an investment in the fund has increased or decreased each period (assuming reinvestment of all dividends and distributions).  Certain information reflects financial results for a single fund share.

The financial statements of the fund as of May 31, 2017, have been audited by PricewaterhouseCoopers LLP (PwC), the fund's independent registered public accounting firm. The report of PwC, along with the fund's financial statements in the fund's annual report for the fiscal year ended May 31, 2017, has been incorporated by reference into the SAI. Copies of the fund's most recent annual report are available upon request.

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