Diamond Offshore Drilling

Diamond Offshore Drilling, Inc.

Company type	Public (formerly)
Industry	Offshore drilling
Founded	1970
Founder	Don McMahon (as Diamond M Drilling Company)
Defunct	September 2024 (2024-09)
Fate	Acquired by Noble Corporation
Headquarters	Katy, Texas , United States
Area served	Worldwide (including Australia, Brazil, Mexico, Scotland, Singapore, Norway, United States)
Products	Offshore drilling services
Parent	Noble Corporation (since September 2024)

Diamond Offshore Drilling, Inc. is a contractor specializing in offshore drilling, headquartered in Katy, Texas. It maintains significant offices across Australia, Brazil, Mexico, Scotland, Singapore, and Norway.

The firm manages a fleet of 15 drilling units, comprising 11 semi-submersible platforms alongside 4 drillships. In September 2024, Diamond Offshore became part of Noble Corporation following their completed acquisition.

History

During the early 1960s, Don McMahon purchased Brewster-Bartle and established Diamond M Drilling Company, marking its entry into offshore drilling. Diamond M transitioned to a publicly traded company in 1970. Subsequently, Kaneb Services acquired it for $102 million before selling it to Loews Corporation in 1989 for $48.5 million.

In 1992, Diamond M procured ODECO from Murphy Oil at a cost of $358 million and adopted the name Diamond Offshore Drilling, Inc. the following year. The company re-entered public markets in October 1995 on the New York Stock Exchange. The acquisition of Arethusa for $516 million in stock occurred in 1996.

Diamond Offshore placed an order for a drillship valued at $655 million with Hyundai Heavy Industries in May 2012. After ceasing its quarterly dividend payments in September 2016, the company was removed from the S&P 500 Index.

By 2019, key clients included Hess Corporation (28.9%), Occidental Petroleum (20.6%), Petrobras (19.5%), and BP (3.1%), with over half (52.5%) of revenue generated from U.S. operations.

The firm filed for bankruptcy protection in April 2020 amid the oil price downturn triggered by the COVID-19 pandemic. It faced public scrutiny for utilizing CARES Act funds—intended for small businesses—to provide bonuses to executives.

In June 2024, Noble Corporation declared a $1.6 billion acquisition deal involving cash and stock for Diamond Offshore, which was completed by September.

Asbestos exposure among workers

In 1989, Diamond's predecessor acquired six rigs from Kaneb Management's predecessor entity. Some former Kaneb employees who continued under Diamond later initiated lawsuits claiming injuries due to asbestos exposure during their Kaneb tenure. A 2013 SEC filing by Diamond acknowledged that its equipment had been involved in the "manufacture and use of asbestos-containing drilling mud," while seeking indemnity against related claims.