DETROIT — Robert Rubin's resignation from the Ford Motor Co. board could mean that Citigroup Inc., where he also serves on the board, plans to talk to Ford about a loan or about advising the struggling automaker on the possible sale of its credit arm, some industry analysts say.

Rubin, a former U.S. treasury secretary, resigned from Ford's board on Thursday, citing potential conflict of interest with his duties at Citigroup, the nation's biggest financial institution. Rubin also is chairman of Citigroup's executive committee and is a member of the chairman's office.

Some analysts said the move announced yesterday may be a sign that the Ford family will need financing for an alliance with another company or to take the automaker private. Another analyst said Citigroup may also advise Ford or someone else on the possible sale of the Ford credit arm.

In a letter to Ford Chairman and Chief Executive Bill Ford, Rubin said he needed to step down as the Ford board begins a review of the automaker's strategic options.

"Citigroup's multifaceted relationship with Ford could raise a question whether my relationship with Ford and Citigroup creates an appearance of conflict. Although no conflict currently exists and while I would have liked to remain involved, I have with great regret concluded that I should resign from the board at this time," Rubin said in the letter.

Rubin, who was on the Ford board for six years, said in the letter that he was pleased Ford had hired the banker and merger specialist Ken Leet to help plot the company's future.

Dearborn-based Ford lost $1.4 billion during the first half of the year, and its sales and market share have dropped. The company recently announced production cuts and is in the midst of accelerating its "Way Forward" restructuring plan. Bill Ford confirmed this week that Ford is exploring alliances with other companies.

The Wall Street Journal reported Wednesday that Bill Ford has approached Nissan-Renault CEO Carlos Ghosn about joining their global alliance, should a deal between General Motors Corp. and Nissan-Renault not work out.

A Ford spokesman said the automaker wouldn't comment on such speculation. He also wouldn't comment on reports that former Ford Chief Executive Jacques Nasser was leading a group interested in buying the Ford-owned Jaguar brand.

Jim McTevia, a Michigan-based corporate turnaround specialist, said Ford, while losing money, is not in such poor financial condition that board members would start bailing out.

The price of buying back all of Ford's stock is far less at present than the value of the company's assets, McTevia said. Ford's market capitalization, or the value of its stock, is about $15 billion, and company officials said last month that it had about $23 billion in cash.

Ford shares rose 24 cents, or 3.1 percent, to close at $8 on the New York Stock Exchange.

"It's entirely probable that Citigroup, being the size of an institution they are, would have the ability to finance the Ford family buying their stock back," McTevia said. The Ford family controls 40 percent of the voting shares of the company.

But Pete Hastings, an auto industry corporate bonds analyst with Morgan Keegan & Co. Inc. in Memphis, Tenn., said it's more likely that Citigroup would advise Ford or a potential buyer on a deal for Ford Motor Credit.

Gerald Meyers, former chairman of American Motors Corp. who now teaches leadership at the University of Michigan, said the Ford family could take the company private, fix its problems and then sell stock once again for a large profit.

"It's not a dead company. It's just been poorly managed," he said.

Nearly all banks, including Citigroup, have relationships with Ford or its credit arm, Hastings said, but that wouldn't necessarily trigger Rubin's resignation. Advising Ford on a bigger deal, or the possibility of a larger loan, however, might create an appearance of a conflict and cause the resignation, Hastings said.

Rubin is doing the right thing by resigning because if a deal involving Citigroup takes place, he would face scrutiny from the Securities and Exchange Commission, McTevia said.

Rubin served as the Treasury Department secretary in the Clinton administration from 1995 to 1999.

Bill Ford said in a statement yesterday that Rubin "brought strategic thinking to every situation and has been a wise and generous counselor to me and to the company. However, I understand and respect Bob's prudent decision to resign as we continue to explore future strategic options."