US investors and analysts said Thursday Chevron Corp., the second-largest US oil company, might have to boost its bid for Unocal Corp. to counter the 18.5 billion-dollar cash bid offered by China National Offshore Oil Company.

"In all likelihood, they will have to raise their bid to satisfy shareholders because CNOOC's bid of all cash is almost 10 percent higher," said an analyst at Connecticut-based John S .Herold Inc. "Unocal shareholders deserve more from Chevron."

Unocal Corp. said its board's recommendation in favor of the Chevron's bid remained in effect, but it would review CNOOC's all cash offer.

The Federal Trade Commission, the US antitrust regulator, approved Chevron's takeover plan on June 10, and the US Securities and Exchange Commission would approve the document soon. CNOOC's takeover plan had to be reviewed by the US Committee for Foreign Investment for national security concerns.

Lee Raymond, Chief Executive Officer of Exxon Mobil Corp., the largest US oil company, said earlier that it would be a "big mistake" for the United States to block the bid. "You have to have free trade." The US business community worried that a block from the US government would affect their investment interests in China.

Source: Xinhua