NEW YORK (Bloomberg) Bermuda-domiciled Kosmos Energy Ltd, the oil and gas exploration and production company owned by Warburg Pincus LLC and Blackstone Group LP, was seeking to raise as much as $540 million yesterday in an initial public offering after oil gained 48 percent in a year to a 32-month high.Kosmos was offering 30 million shares at $16 to $18 each, according to a filing with the US Securities and Exchange Commission. The company has about a 23 percent stake in Ghana’s Jubilee oilfield, the biggest offshore discovery in West Africa in a decade, according to the prospectus.“The price of oil has certainly gone higher, and that improves the perceived value of the company,” said Hugh Johnson, who oversees about $2 billion as chairman of Albany, New York-based Hugh Johnson Advisors LLC. “Private equity folks try to be good at the timing of their exit, and I think they’re trying to do that now.”Warburg and Blackstone may be capitalising on the climb in crude oil and a recent spate of private equity-backed IPOs. While crude dipped amid a recent sell-off in commodities, it has rallied since its December 2008 low, increasing more than threefold as of April 11. Companies owned by leveraged buyout firms raised about $19.5 billion worldwide through IPOs in the first quarter, more than half their total for all of 2010, data compiled by Bloomberg and London-based Preqin Ltd. shows.Kosmos agreed in 2009 to sell assets including the Jubilee field to Exxon Mobil Corp for an enterprise value of about $4 billion, according to a person with knowledge of the situation. Exxon terminated the agreement last year.Since 2009, Kosmos has further developed the Jubilee project and made more offshore discoveries in Ghana, according to the prospectus. Jubilee is expected to yield 120,000 barrels of oil per day in the third quarter of this year. The Jubilee field started production in November, and the company began to receive revenue from its share of the output early this year.Brent crude futures traded in London reached $127.02 on April 11, the highest since August 2008. They tumbled 13 percent last week as the death of Osama bin Laden and a strengthening dollar triggered a five-day rout in commodity prices.“The challenge for any IPO in the energy sector right now is that the sector has recently fallen out of favour, and the pricing will be challenged by that,” said Alan Gayle, senior investment strategist at RidgeWorth Capital Management in Richmond, Virginia, which oversees $48 billion. “Trying to issue an IPO in the face of a market that’s going the other way just represents one more hurdle.”