SINGAPORE, Feb 21 Oil services firm Aban Singapore Pte Ltd, a unit of Aban Offshore A

SINGAPORE, Feb 21 (Reuters) Oil services firm Aban Singapore Pte Ltd, a unit of Aban Offshore , has sold $150 million of convertible bonds to four investors in a private placement, sources said on Wednesday.

The bonds, which are due to mature in 2014, were sold to finance the purchase of shares in Norwegian offshore oil services firm Sinvest ASA , two people involved in the bond sale told Reuters.

Merrill Lynch was lead manager for the bond deal.

One source said the four investors would have a combined stake of around 10 percent in Aban Singapore when these bonds are converted into shares.

He said the bond investors would have the option of converting to shares if Aban Singapore is listed on a stock exchange before 2014.

Earlier this week, Aban Offshore through its subsidiaries, Aban Singapore Pte Ltd and Aban International Norway AS, raised its stake in Norway's Sinvest to 97 percent.

Sinvest has a market value of $1.3 billion.

Officials at Aban Offshore did not say when and where Aban Singapore was expected to be listed.

Aban Singapore and Sinvest both have offshore drilling rigs under construction at yards owned by Singapore's Keppel Corp and SembCorp Marine .

Aban Offshore provides oil field services for offshore exploration and the production of hydrocarbons. It is part of the Indian conglomerate Aban Group, whose interests range from wind energy and conventional power generation, to information technology and hotels.

Singapore has become an important global centre for the construction of oil rigs and offshore oil business, with Keppel Corp. and Sembcorp Marine building 60 percent of the world's oil rigs.

REUTERS SRS HS1722