LONDON (Bloomberg) — Apax Partners Worldwide LLP and Permira Advisers LLP are considering a sale of Bermuda-based Intelsat Ltd., the world’s biggest commercial-satellite operator, for as much as $6 billion, two people familiar with the talks said.Credit Suisse Group is advising the two buy-out firms on the transaction, said the people, who declined to be identified before an agreement is reached. Possible buyers include New York-based Blackstone Group LP or other private-equity firms.

If the sale is successful, the two firms, together with partners Madison Dearborn Partners LLC and Apollo Management LP, stand to reap about 10 times the $515 million of cash they used to buy Intelsat in 2003. A year later, Intelsat bought rival operator PanAmSat Holding Corp. for $3.2 billion to create the world’s No. 1 satellite operator.

“Being private has been good for us so far,” Intelsat chief executive officer David McGlade said in an interview on April 13. “We’re always open to other capital structures and view them all the time.” He declined to comment on potential capital market transactions.

Intelsat spokeswoman Dianne VanBeber didn’t return voice mail and e-mail messages from Bloomberg News before business hours in Washington. The Wall Street Journal reported the possible sale earlier today. Spokespeople for Apax and Blackstone declined to comment and officials at Permira didn’t immediately return calls.

Buy-out firms use a combination of their own funds and debt to pay for takeovers. They typically seek to expand the companies they buy or to improve their performance before selling them within five years. Intelsat is saddled with about $11 billion of long-term debt.

Intelsat has customers including Time Warner Inc. and News Corp. and has 51 satellites, pushing it ahead of SES Global SA’s 43 satellites.

It provides coverage in more than 220 countries. Among Intelsat’s customers are the US military, France Telecom SA and US television networks ABC and CBS.

Founded in 1964 by governments around the world, Intelsat transmitted video of Neil Armstrong’s 1969 walk on the moon. The company had a net loss of $369 million on revenue of $1.66 billion in 2006, according to a Securities & Exchange Commission filing. Operating income advanced more than fourfold to $402 million.