NEW YORK, SEPT. 17 -- Normally, an investor who wishes to buy a company keeps raising the price until the seller says yes.

In the case of UAL Corp., however, its unions keep lowering the amount they are willing to pay for the company -- and so far the board of directors still hasn't said no.

In the latest twist in what has become one of the longest-running sagas on Wall Street, sources said the three unions are considering reducing their standing bid of $201-a-share, or $4.4 billion, for UAL, United Airlines's parent.

Given the deteriorating outlook for airlines, made worse by escalating fuel costs in the wake of the Persian Gulf crisis, the sources said the unions were compelled to offer less for the carrier if they are to have any hope of attracting financing for the proposed buyout.

"It's a question of being realistic in today's environment. The clear focus should be on what can get done, not on what they'd {the unions} like to see," said a source close to the deal who asked to remain unidentified.

A lowering of the price would mark the second time that the unions -- of pilots, machinists and flight attendants -- have reduced their offer since they began trying to buy the company three years ago.

While the sources said they did not know what new offer the unions were considering, independent airline analysts estimated that a realistic upper range for a new bid was between $165 and $175 a share. Both UAL and the unions declined to comment, but the market reacted as though it thought a lower bid was in the making, sending UAL's stock down $1.50 to close at $97.50.

The $201-a-share bid, made in April, has been stymied by the refusal of the unions' bankers to lend the money for it. That was the same hang-up that forced the unions to drop their original $300-a-share bid, which collapsed last October and helped drag down the Dow Jones industrial average nearly 200 points.

To help assure that the latest deal doesn't meet the same fate, the unions hired former Chrysler Motors Corp. chairman Gerald Greenwald, who gets paid $9 million even if the buyout doesn't go through. If it does, UAL would become the nation's largest employee-owned company.

The challenge would be getting UAL's board of directors to accept a lower price for the company than the $201-a-share that it already has accepted in principle.

"The lower the price gets, the harder it gets {for the board} to justify it," said Robert J. Joedicke, a veteran airline specialist with Lehman Brothers Inc. The unions would like to make a last-ditch attempt to buy UAL, even though the recent oil price jump and accompanying slump in the stock market have worsened prospects for the transaction, according to sources familiar with the unions' position.

The unions have to act before Oct. 9, the latest deadline set by UAL management for obtaining financing for the outstanding $201-a-share bid.

In a step on Friday interpreted by some sources as an indication the unions might be getting close to putting together a new bid for UAL, the unions formally severed an alliance with Coniston Partners, a New York investment firm that is UAL's largest shareholder with a stake of nearly 12 percent.The breaking of the alliance with Coniston was largely a technical matter, which relieves the unions of having to publicly disclose in advance their actions regarding UAL, the sources said.

The unions' apparent desire to keep private their plans could indicate that the unions are moving closer to reaching a deal, the sources said.