TUSHAR MATHUR HAD every reason to expect Bank of America’s best deal on a mortgage. After all, the 31-year-old software developer kept a checking account and a credit card with the giant consumer bank. He had a ridiculously high credit score — 785 — and was willing to make a 20% down payment on a brand-new four-bedroom colonial in the Atlanta suburbs.

But a funny thing happened on the way to closing the deal on his first home. After reviewing his application, he says, a Bank of America representative offered him a rate of 6.5%, nowhere near as good as the 5.8% to 6.2% rates he had been quoted from other lenders. And the difference wasn’t lunch money: Had he gone with Bank of America (BAC: 26.53, +3.74, +16.41%), his mortgage payments, over the life of the loan, would have cost an extra $21,000 more than the deal he ultimately accepted. “They were higher than anybody, and I don’t know why,” he says of his branch’s offer.

For its part, Bank of America declines to discuss its offer to Mathur or the details on how it makes such decisions. But ask a financial-industry consultant and he’ll tell you what may have been going on: something called price optimization. That’s a fancy way of saying Mathur’s rate was partially based on what the bank’s computer thought he might be willing to pay. Sound familiar? Yes, banks have started to play the same elaborate — and convoluted — pricing game that airlines, hotels and a host of other industries have perfected, charging customers different prices for an identical product or service. Only what’s at stake isn’t a one-way ticket to Phoenix that might cost one customer $80 and another $800, but some of the largest financial transactions most folks will ever make: mortgages, car loans and home-equity lines of credit.

The move to price optimization, which most banks are still only testing, has been spurred by the mammoth challenges threatening the $6 trillion lending industry. Subprime lending losses contributed to a 45% drop in bank earnings last quarter, and mortgage-loan volume is expected to tumble 16% this year. Analysts say banks are looking to price optimization as a relatively quick and easy way to boost a sagging bottom line by as much as 5 to 10% in three to six months. “The return on investment is huge,” says Terry Kuester, a banking consultant with Deloitte & Touche. “It’s a huge opportunity for banks.”

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