Exxon Mobil is the world's largest listed oil company

Last week Exxon posted a quarterly profit of $9.9bn (£5.55bn), the largest in US corporate history, on the back of record oil and gas prices.

King Win Laurel has filed papers with the Securities and Exchange Commission offering to buy the firm in a dollars and yuan deal worth $70 a share.

Exxon said it did not believe King was "financially capable" of such an offer.

A Reuters reporter visited King Win Laurel's registered address in China, and found it to be a 14th-floor flat in a tower block on the outskirts of Beijing - apparently inhabited by a man in his mid-20s.

SEC documents included both the Beijing contact address and one in Auckland, New Zealand.

Documents needed

Texas-based Exxon is the world's biggest publicly-traded oil company.

It has been benefiting from the rising cost of oil, brought on by the two hurricanes which hit the Gulf of Mexico in late summer, disrupting output.

King Win Laurel, which said it was incorporated in New Zealand on 21 October, said the offer was subject to financing and included incentives for shareholders if the price of oil kept on rising.

But Exxon said it had received no communications from China.

"We do not believe that King Win Laurel Limited is financially capable of making such a tender offer," Exxon spokesman Dave Gardner said in a statement.

It is not out of the realm of possibility that the Chinese government could fund a bid for Exxon

Jon Cartwright, BOSC

The Chinese outfit would have needed to submit documentation to get access to the SEC's electronic filing system and provide a sworn statement verifying its identity.

"Any person who meets requirements and certifies that they are who they say they are can file," said SEC spokesman John Heine.

"Of course there are all sorts of possible consequences if someone is abusing the system."

The booming Chinese economy is in need of increasing oil supplies, and earlier this year its oil producer CNOOC withdrew an $18.5bn (£10.4bn) bid for US firm Unocal, after American political opposition.

"It is not out of the realm of possibility that the Chinese government could fund a bid for Exxon, so we can't ignore it entirely, even though that's my initial inclination," said debt analyst Jon Cartwright of BOSC.

Previous attempt

This is not the first time the owners of King Win Laurel have tried to get into the acquisitions business.

In 2003, they started a company in New Zealand with almost exactly the same name - King Win Laurel International - and the same registered address in Auckland.

That time, the target was a fast food company called Restaurant Brands, and the bid was thrown out because New Zealand's Takeover Panel said it did not comply with takeover rules.

The previous company was run by Ying Wang and Xiufeng Zhang - the registered director of the current King Win - with part of the ownership lodged in a UK-registered company, Kingwin Holding (UK).

Both the UK and New Zealand firms were dissolved in early 2005.

UK company documents say that Mr Wang is 25 years old, while Mr Zhang is 33.