Temasek Holdings cut its energy holdings in the year through March as the wealth fund's assets jumped almost a fifth to a record US$197 billion (S$266 billion).
However, exiting an oil-rig investment in Mexico has not proven so easy.
Temasek and investment firm Ares Management LP, which each own 22.5 per cent of Integradora de Servicios Petroleros Oro Negro, failed to convince other shareholders to agree to a sale of the company, according to a bond document released by the driller in January.
Oro Negro in April hired advisers to find "strategic alternatives" for the business whose main investor, Mexican private equity firm Axis Group, holds 49.5 per cent.
The value of Oro Negro's US$900 million of bonds has slid more than 20 per cent over the past nine months, and it has paid bondholders US$875,000 to ease some debt covenants, according to a May 18 statement from the bonds' trustee.
HIT BY SLUMP
A situation where the equity guys are not talking means they will probably not come up with more equity. Oro Negro is suffering from the slump in offshore drilling.
MR ARNE EIDSHAGEN, a money manager at Alfred Berg Kapitalforvaltning AB in Oslo, who cut his holding of Oro Negro bonds
Since Temasek bought its stake in 2012, oil prices have plunged and a lack of agreement among shareholders is not helping the outlook.
"A situation where the equity guys are not talking means they will probably not come up with more equity," said Mr Arne Eidshagen, a money manager at Alfred Berg Kapitalforvaltning AB in Oslo, who cut his holding of Oro Negro bonds last year.
"Oro Negro is suffering from the slump in offshore drilling."
Both Mr Miguel Angel Villegas, Oro Negro's chief financial officer, and Ares declined to comment in a July 7 e-mail. Axis did not respond to e-mail and telephone calls.
"As the matter is before the courts, it would not be appropriate for us to discuss the outcome" of the shareholders' legal action, Mr Stephen Forshaw, a Singapore- based spokesman for Temasek, said in a July 6 e-mail. He added that Temasek does not flag its intentions for any of its investments.
Ares and Temasek notified Oro Negro of their intention to "explore alternatives to divest their stake" and to "solicit offers from third parties to sell 100 per cent of the capital stock", Oro Negro had said in its January document.
Shareholders that were not named in the document filed a lawsuit requesting that ambition be considered null and void.
An injunction restraining Ares and Temasek from soliciting third- party offers was then granted, according to the document.
Temasek began investing in Oro Negro in 2012 as Mexico reined in the state's 75-year oil monopoly to boost production, driving a boom in rig orders funded by bonds.
Temasek has ridden a rally in global equities that helped its assets increase 19 per cent to a record $266 billion in the year to March 31, it reported on Tuesday. That is more than double that a decade ago. The proportion of its energy and resources assets fell to 5 per cent from 6 per cent.