ITEM 1.    BUSINESS

General

Unless the context indicates otherwise, the terms “we,” “our,” “ours,” “us” and the “Company” refer to SEACOR Holdings Inc. and its consolidated subsidiaries. “SEACOR” refers to SEACOR Holdings Inc., incorporated in 1989 in Delaware. “Common Stock” refers to the common stock, par value $.01 per share, of SEACOR. The Company’s fiscal year ended on December 31, 2015 .

SEACOR’s principal executive office is located at 2200 Eller Drive, P.O. Box 13038, Fort Lauderdale, Florida 33316, and its telephone number is (954) 523-2200. SEACOR’s website address is www.seacorholdings.com . The reference to SEACOR’s website is not intended to incorporate the information on the website into this Annual Report on Form 10-K.

The Company’s Corporate Governance documents, including the Board of Directors’ Audit Committee, Compensation Committee and Nominating and Corporate Governance Committee charters are available, free of charge, on SEACOR’s website or in print for stockholders.

All of the Company’s periodic reports filed with the Securities and Exchange Commission (“SEC”) pursuant to Section 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended, are available, free of charge, on SEACOR’s website, including its Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K and any amendments to those reports. These reports and amendments are available on SEACOR’s website as soon as reasonably practicable after the Company electronically files the reports or amendments with the SEC. They are also available at the SEC’s Public Reference Room at 100 F Street, N.E., Washington, D.C. 20549. Information as to the operation of the SEC’s Public Reference Room can be obtained by calling the SEC at 1-800-SEC-0330. The SEC maintains a website (www.sec.gov) that contains reports, proxy and information statements and other information.

Segment and Geographic Information

SEACOR and its subsidiaries are in the business of owning, operating, investing in and marketing equipment, primarily in the offshore oil and gas, shipping and logistics industries. The Company conducts its activities in the following reporting segments:

Potential Spin-off of Offshore Marine Services

On December 1, 2015, SEACOR Marine Holdings Inc. (“SMH”), a subsidiary of SEACOR that is the parent company of the Offshore Marine Services business segment, issued $175.0 million aggregate principal amount of its 3.75% Convertible Senior Notes due December 1, 2022 to investment funds managed and controlled by The Carlyle Group. The transaction contemplates the potential separation of SMH from the Company via a spin-off of SMH to SEACOR's shareholders (the "SMH Spin-off"). The Company is still considering whether or not to effect a SMH Spin-off and is under no obligation to do so. SEACOR continues to provide Offshore Marine Services administrative services and support business development initiatives and, if the SMH Spin-off were to occur, would likely continue to do so during a transition period for some time after a SMH Spin-off.

Discontinued Operations

On March 16, 2012, the Company sold SEACOR Environmental Services Inc. ("SES") to J.F. Lehman & Company ("JFL"), a leading middle-market private equity firm (the "SES Business Transaction"). SES included National Response Corporation ("NRC"), a provider of oil spill response services in the United States; NRC Environmental Services Inc., a provider of environmental and industrial services on the West Coast of the United States; SEACOR Response Ltd., a provider of oil spill response and emergency response services to customers in international markets; and certain other subsidiaries (collectively the “SES Business”). For all periods presented herein, the Company has reported the historical financial position, results of operations and cash flows of the SES Business as discontinued operations.

On December 31, 2012, the Company sold SEACOR Energy Inc. ("SEI"), its energy commodity and logistics business, to Par Petroleum Corporation. For all periods presented herein, the Company has reported the historical financial position, results of operations and cash flows of SEI as discontinued operations.

On January 31, 2013, the Company completed the spin-off (the "Era Spin-off") of Era Group Inc. ("Era Group"), the company that operated SEACOR's Aviation Services business segment, by means of a dividend to SEACOR's stockholders of all the issued and outstanding common stock of Era Group. Era Group filed a Registration Statement on Form 10 with the SEC that was declared effective on January 14, 2013. Era Group is an independent company whose common stock is listed on the New York Stock Exchange under the symbol "ERA." For all periods presented herein, the Company has reported the historical financial position, results of operations and cash flows of Era Group as discontinued operations.

Offshore Marine Services

Business

Offshore Marine Services operates a diverse fleet of support vessels primarily servicing offshore oil and gas exploration, development and production facilities worldwide. The vessels deliver cargo and personnel to offshore installations; handle anchors and mooring equipment required to tether rigs to the seabed; tow rigs and assist in placing them on location and moving them between regions; and carry and launch equipment such as remote operated vehicles or “ROVs” used underwater in drilling and well installation, maintenance, and repair. In addition, Offshore Marine Services' vessels provide accommodations for technicians and specialists, and provide standby safety support and emergency response services. Offshore Marine Services also operates a fleet of lift boats in the U.S. Gulf of Mexico supporting well intervention, work-over, decommissioning and diving operations. In non-oil and gas industry activity, Offshore Marine Services operates vessels primarily used to move personnel and supplies to offshore wind farms in Europe. Offshore Marine Services contributed 35% , 40% and 45% of consolidated operating revenues in 2015 , 2014 and 2013 , respectively.

For a discussion of risk and economic factors that may impact Offshore Marine Services' financial position and its results of operations, see “Item 1A. Risk Factors” and "Offshore Marine Services" in "Item 7. Management's Discussion and Analysis of Financial Condition and Results of Operations."

Equipment and Services

The following tables identify the types of vessels that comprise Offshore Marine Services’ fleet as of December 31 for the indicated years. “Owned” are majority owned and controlled by the Company. “Joint Ventured” are owned by entities in which the Company does not have a controlling interest. “Leased-in” may either be vessels contracted from leasing companies to which the Company may have sold such vessels or vessels chartered-in from other third party owners. “Pooled” are owned by entities not affiliated with Offshore Marine Services with the revenues or results of operations of these vessels being shared with the revenues or results of operations of certain vessels of similar type owned by Offshore Marine Services based upon an agreed formula. “Managed” are owned by entities not affiliated with the Company but operated by Offshore Marine Services for a fee.

																	Owned Fleet
		Owned			Joint Ventured			Leased-in			Pooled or Managed			Total			Average Age			U.S.- Flag			Foreign- Flag
2015
Anchor handling towing supply		13			1			4			—			18			15			9			4
Fast support		23			7			1			3			34			10			8			15
Mini-supply		4			2			—			1			7			15			—			4
Standby safety		24			1			—			—			25			35			—			24
Supply		7			12			2			3			24			14			2			5
Towing supply		2			1			—			—			3			13			—			2
Specialty		3			5			—			1			9			20			—			3
Liftboats		13			—			2			—			15			13			13			—
Wind farm utility		35			3			—			—			38			7			—			35
		124			32			9			8			173			15			32			92
2014
Anchor handling towing supply		13			1			4			—			18			14			9			4
Fast support		21			7			4			3			35			11			7			14
Mini-supply		4			2			—			1			7			14			—			4
Standby safety		24			1			—			—			25			34			—			24
Supply		7			9			6			3			25			13			2			5
Towing supply		2			1			—			—			3			12			—			2
Specialty		3			5			—			1			9			19			1			2
Liftboats		13			—			2			—			15			12			13			—
Wind farm utility		33			3			—			—			36			6			—			33
		120			29			16			8			173			15			32			88
2013
Anchor handling towing supply		14			1			3			—			18			13			11			3
Fast support		25			7			7			3			42			12			10			15
Mini-supply		4			2			2			—			8			13			—			4
Standby safety		24			1			—			—			25			33			—			24
Supply		9			5			9			4			27			11			4			5
Towing supply		2			1			—			—			3			11			—			2
Specialty		3			5			—			4			12			18			1			2
Liftboats		14			—			1			—			15			11			14			—
Wind farm utility		32			2			—			—			34			5			—			32
		127			24			22			11			184			14			40			87

Anchor handling towing supply (“AHTS”) vessels are used primarily to support offshore drilling activities in the towing, positioning and mooring of drilling rigs and other marine equipment. AHTS vessels are also used to carry and launch equipment such as ROVs used underwater in drilling and well installation, maintenance, and repair and transport supplies and equipment from shore bases to offshore drilling rigs, platforms and other installations. The defining characteristics of AHTS vessels are horsepower (“bhp”), size of winch in terms of “line pull” and wire storage capacity. Offshore Marine Services’ fleet of AHTS vessels has varying capabilities and supports offshore mooring activities in water depths ranging from 300 to 8,000 feet. Most modern AHTS vessels are equipped with dynamic positioning ("DP") systems ¹ to enable them to maintain a fixed position in close

proximity to a rig or platform. As of December 31, 2015 , eight of the 13 owned AHTS vessels were equipped with DP-2 and two were equipped with DP.

Fast support vessels ("FSVs") are used primarily to move cargo and personnel to and from offshore drilling rigs, platforms and other installations. They range from 130 to 210 feet in length, are capable of speeds between 25 and 35 knots and have enhanced cargo carrying capacities enabling them to support both drilling operations and production services. Newer FSVs support deepwater drilling and production and are equipped with DP-2, firefighting equipment and ride control systems for greater comfort and performance. As of December 31, 2015 , ten of the 23 owned FSVs were equipped with DP-2 and five were equipped with DP.

Mini-supply vessels are approximately 145 to 165 feet in length and typically carry deck cargo, liquid mud, methanol, diesel fuel and water. These vessels are typically used to support construction projects, maintenance work, certain drilling support activities and production support. In this vessel class, the new generation of vessels is also equipped with DP capability. As of December 31, 2015 , three of the four owned mini-supply vessels were equipped with DP.

Standby safety vessels typically remain on location proximate to offshore rigs and production facilities to respond to emergencies. These vessels carry special equipment to rescue personnel and are equipped to provide first aid and shelter. These vessels sometimes perform a dual role, also functioning as supply vessels.

Supply vessels and towing supply vessels are generally more than 200 feet in length and are used to deliver cargo to rigs and platforms where drilling and work-over activity is underway or to support construction work by delivering pipe to vessels performing underwater installations. Supply vessels are distinguished from other vessels by the total carrying capacity (expressed as deadweight: “dwt”), available area of clear deck space, below-deck capacity for storage of mud and cement used in the drilling process and tank storage for water and fuel oil. Larger supply vessels usually have deck fittings to assist in handling cargo and are often fitted with a crane. The ability to hold station in open water and moderately rough seas is a key factor in differentiating supply vessels. To improve station keeping ability, most modern supply vessels have DP capabilities. Accommodations are also an important feature of supply vessels. As drilling becomes more complex, supply vessels often house third-parties who are specialists in various phases of the drilling process. Towing supply vessels perform similar cargo delivery functions to those handled by supply vessels. They are, however, equipped with more powerful engines (4,000 – 8,000 bhp) and winches, giving them the added capability to perform general towing functions, buoy setting and limited anchor handling work. As of December 31, 2015 , four of the nine owned supply and towing supply vessels were equipped with DP-2 and one was equipped with DP.

Specialty vessels include anchor handling tugs, accommodation, line handling and other vessels. These vessels generally have specialized features adapting them to specific applications including offshore maintenance and construction services, freight hauling services and accommodation services.

Liftboats provide a self-propelled, stable platform to perform production platform construction, inspection, maintenance and removal; well intervention and work-over; well plug and abandonment; pipeline installation and maintenance; and diving operations . Liftboats are categorized by the length of their jacking legs (160 ft. to 265 ft. for the Company's liftboats), which determines the water depth in which these vessels can work. Secondary features are crane lifting capacity and reach, clear deck area, electrical generating power and accommodation capacity.

Wind farm utility vessels are used primarily to move personnel and supplies to offshore wind farms. There are two main types of vessels; Windcats and Windspeeds. The Windcat series feature a catamaran hull with flush foredeck, providing a stable platform from which personnel can safely transfer to turbine towers, and are capable of speeds between 25 and 31 knots. The Windspeed series are rapid response vessels with a maximum speed of 38 knots, which are used for light work during the construction and operational periods of offshore wind farms. All the wind farm utility vessels have been built since 2004.

As of December 31, 2015 , in addition to its existing fleet, Offshore Marine Services had new construction projects in progress including seven U.S.-flag, DP-2 fast support vessels scheduled for delivery between the second quarter of 2016 and the first quarter of 2019; four U.S.-flag, DP-2 supply vessels for delivery between the second quarter of 2016 and first quarter of 2019, two of which are to be sold upon delivery to Mantenimiento Express Maritimo, S.A.P.I. de C.V., a 50% or less owned company; two foreign-flag specialty vessels scheduled for delivery during 2017; and three foreign-flag wind farm utility vessels scheduled for delivery during 2016.

______________________

United States, primarily U.S. Gulf of Mexico. As of December 31, 2015 , 41 vessels were operating in the U.S. Gulf of Mexico, including 27 owned, six leased-in, five joint ventured, two pooled and one managed. Offshore Marine Services’ vessels in this market support deepwater anchor handling with its fleet of AHTS vessels, fast cargo transport with its fleet of FSVs, general cargo transport with its platform supply vessels, and its fleet of liftboats supporting well intervention, work-over, decommissioning and diving operations.

Africa, primarily West Africa. As of December 31, 2015 , 22 vessels were operating in West Africa, including 13 owned, two leased-in, four joint ventured, one pooled and two managed. Offshore Marine Services' vessels operating in this area generally support large-scale, multi-year projects for major oil companies, primarily in Angola and Ghana. The other vessels in this region operate from ports in the Republic of the Congo and Gabon.

Middle East. As of December 31, 2015 , 23 vessels were operating in the Middle East region, including 17 owned, four joint ventured and two managed. Offshore Marine Services’ vessels operating in this area generally support activities in Azerbaijan, Egypt and countries along the Arabian Gulf and Arabian Sea, including the United Arab Emirates and Qatar.

Brazil, Mexico, Central and South America. As of December 31, 2015 , 17 vessels were operating in Mexico, including three owned, one leased-in and 13 joint ventured through the Company's 49% noncontrolling interest in Mantenimiento Express Maritimo, S.A.P.I. de C.V. (“MexMar”). These vessels, consisting of a fleet of FSVs and platform supply and anchor handling towing supply vessels, provide support for exploration and production activities in Mexico with a focus on ultra-deep water. In addition, two owned vessels were operating in Brazil.

Europe, primarily North Sea. As of December 31, 2015 , 25 vessels were operating in the North Sea providing standby safety and supply services, including 24 owned and one joint ventured. Demand for standby services developed in 1991 after the United Kingdom passed legislation requiring offshore operators to maintain higher specification standby safety vessels. The legislation requires a vessel to “stand by” to provide a means of evacuation and rescue for platform and rig personnel in the event of an emergency at an offshore installation. In addition, through a 75% controlling interest in the wind farm utility fleet, 37 vessels were operating in the North Sea, including 34 owned and three joint ventured, supporting the construction and maintenance of offshore wind turbines.

Asia. As of December 31, 2015 , six vessels were operating in Asia, including four owned and two joint ventured. Offshore Marine Services’ vessels operating in this area generally support exploration and seasonal construction programs. To date, Offshore Marine Services’ largest markets in this area have been Vietnam, Indonesia and Russia.

Seasonality

The demand for Offshore Marine Services' liftboat fleet in the U.S. Gulf of Mexico is seasonal with peak demand normally occurring during the summer months. As a consequence of this seasonality, the Company typically schedules drydockings or other repair and maintenance activity during the winter months.

Customers and Contractual Arrangements

Offshore Marine Services’ principal customers are major integrated oil companies, large independent oil and gas exploration and production companies and emerging independent companies. Consolidation of oil and gas companies through mergers and acquisitions over the past several years has reduced Offshore Marine Services’ customer base. In 2015 , no single customer of Offshore Marine Services was responsible for 10% or more of consolidated operating revenues. The ten largest customers of Offshore Marine Services accounted for approximately 55% of Offshore Marine Services’ operating revenues in 2015 . The loss of one or a few of these customers could have a material adverse effect on Offshore Marine Services’ results of operations.

The Offshore Marine Services segment earns revenues primarily from the time charter and bareboat charter of vessels to customers based upon daily rates of hire. Under a time charter, Offshore Marine Services provides a vessel to a customer and is responsible for all operating expenses, typically excluding fuel. Under a bareboat charter, Offshore Marine Services provides a vessel to a customer and the customer assumes responsibility for all operating expenses and all risk of operation. Vessel charters may range from several days to several years. In the U.S. Gulf of Mexico, time charter durations and rates are typically established in the context of master service agreements that govern the terms and conditions of charter.

Competitive Conditions

Each of the markets in which Offshore Marine Services operates is highly competitive. The most important competitive factors are pricing and the availability and specifications of equipment to fit customer requirements. Other important factors include service, reputation, flag preference, local marine operating conditions, the ability to provide and maintain logistical support given the complexity of a project and the cost of moving equipment from one geographical location to another.

Offshore Marine Services has numerous competitors in each of the geographical regions in which it operates, ranging from international companies that operate in many regions to smaller local companies that typically concentrate their activities in one specific region.

Risks of Foreign Operations

For the years ended December 31, 2015 , 2014 and 2013 , 68% , 57% and 52% , respectively, of Offshore Marine Services’ operating revenues and $8.6 million , $9.9 million and $8.1 million , respectively, of Offshore Marine Services' equity in earnings from 50% or less owned companies, net of tax, were derived from its foreign operations.

Foreign operations are subject to inherent risks, which, if they materialize, could have a material adverse effect on Offshore Marine Services’ financial position and its results of operations. See the risk factor entitled “Risks from the Company’s international operations” in “Item 1A. Risk Factors.”

Inland River Services

Business

Inland River Services operates river transportation equipment used for moving agricultural and industrial commodities and petroleum products on the U.S. Inland River Waterways, primarily the Mississippi River, Illinois River, Tennessee River, Ohio River and their tributaries and the Gulf Intracoastal Waterways. Internationally, Inland River Services has barge operations on the Magdalena River in Colombia and on the Parana-Paraguay River Waterways in Brazil, Bolivia, Paraguay, Argentina and Uruguay. In addition to its primary barge and towboat businesses, Inland River Services also operates and invests in high-speed multi-modal terminal facilities for both dry and liquid commodities; barge fleeting locations in various areas of the U.S. Inland River Waterways; a broad range of service facilities including machine shop and the repair and drydocking of barges and towboats at strategic locations on the U.S. Inland River Waterways; and a transshipment terminal at the Port of Ibicuy, Argentina. Inland River Services contributed 22% , 19% and 17% of consolidated operating revenues in 2015 , 2014 and 2013 , respectively.

For a discussion of risk and economic factors that may impact Inland River Services' financial position and its results of operations, see "Item 1A. Risk Factors" and "Inland River Services" in "Item 7. Management's Discussion and Analysis of Financial Condition and Results of Operations."

Equipment and Services

The following tables identify the types of equipment that comprise Inland River Services’ fleet as of December 31 for the indicated years. “Owned” are majority owned and controlled by the Company. “Joint Ventured” are owned by entities in which the Company does not have a controlling interest. “Leased-in” may either be equipment contracted from leasing companies to which the Company may have sold such equipment or equipment chartered-in from other third party owners. “Pooled” are barges owned by third parties with operating revenues and voyage expenses pooled with certain barges of a similar type owned by Inland River Services and the net results allocated to participants based upon the number of days the barges participate in the pool. For “Pooled” barges, each barge owner is responsible for the costs of insurance, maintenance and repair as well as for capital and financing costs of its own equipment in the pool and pays a daily management fee to Inland River Services for operating the pool.