Mitsubishi UFJ Financial Group’s (ADR: MTU) $3 billion bid to obtain California’s UnionBanCal Corp. (UB) suffered a blow yesterday (Thursday) when a shareholder advisory committee determined the offer price was too low.

“The proposed price does not reflect the strength of UnionBanCal’s strong capital position, the superior credit quality of its assets, and its potential for profitable asset and core deposit growth in the current market environment,” Richard Farman, chairman of the special committee said, The Financial Times reported.

Soon after the $3 billion offer was announced, investors bid the share price higher. Shares closed at $65.46, yesterday, over $2 more than Mitsubishi’s offer price.

The $63-a-share offer, “is not in the best interest of UnionBanCal’s minority stockholders,” the bank said in a statement.

UnionBanCal’s majority stakeholder is, of course, Mitsubishi itself. The Japanese financial group currently controls 65% of UnionBanCal shares. Many analysts anticipate a higher bid as Mitsubishi seeks full control of its American investment.

“If Mitsubishi UFJ offers a little bit more, I think the deal will go through smoothly,” Edwin Merner, president of Tokyo-based Atlantis Investment Research Corp., told Bloomberg News. “Both Wells Fargo & Co. (WFC) and Bank of America Corp. (BAC), the other two big banks in California, will have to back off now for a while, so it’s a great chance for Mitsubishi UFJ.”

The advisory committee said it was opened to continued negotiations with Mitsubishi, lending weight to the theory that a sweeter offer might be all that’s needed to close the deal.

“It is pretty much standard form in the U.S. [to reject an offer]. Those independent directors have a legal obligation to protect the interests of minority shareholders,” Brett Hemsley, banking analyst at HSBC in Tokyo, told FT.

Hemsley went on to say that while a $68 per share offer might seem expensive, compared to the average share price of other beaten down American financial shares, many U.S. banks “have problems that Union Bank of California doesn’t have.”