Tom Givens is not a happy camper.

A longtime holder of a Giant Food Visa credit card, the Franconia resident said he used the card for "everything--food, department stores, gas, post office"--and he loved getting money back for purchases he would have made anyway.

"We found a 1 percent discount on everything we bought to be great," he said.

But now that rebate is going away, like a growing number of such programs that are victims of miscalculations by credit-card banks and changes that are sweeping the credit-card market generally.

Not only are consumer habits changing, making cards less profitable, but growth is slowing sharply. Issuers are increasingly finding they can attract new customers only by luring them away from a competitor or by offering cards to people who previously were considered poor credit risks.

"We are at a turning point in the credit-card industry. Conditions have changed. Consumers have changed," said Robert B. McKinley, head of Inc., a Frederick, Md., firm that tracks credit cards.

Thus, experts say, consumers can expect to see fewer and less-generous rebate programs in the future, and possibly higher introductory "teaser" interest rates, along with new aggressiveness in imposing fees.

Card holders can already see a tightening. Many rebate programs like Giant's have been cut back or eliminated, and others, such as cards that award frequent-flier miles, often impose annual fees.

There also has been increased aggressiveness in imposing fees, along with a shrinking of the "grace period" between the time a purchase is made and the time the bill must be paid to avoid incurring interest charges. A few issuers even charge late fees for payments received after 8 or 10 a.m. on the due date.

Issuers also are emphasizing such marketing techniques as "affinity programs" in which cards are marketed in association with a school, trade or professional association, or charity. Such programs typically provide the affinity partner with a small percentage of the revenue generated, and can thus be marketed as benefiting an organization the card holder may want to support.

As a result, college alumni and long-lost members of honorary societies around the country are getting mailings from institutions they've had no contact with in years.

The market "is intensely competitive, and that level of competition is going to continue," said Janet Eissenstat of the American Bankers Association here. But the competition is likely to take new forms as issuers strive to target their efforts, "marketing the right cards to the right person," she said.

The changes are coming about as credit-card profits, long one of the banking industry's strong points, have hit the wall. Stocks of big card issuers plunged last month when Bank One warned that annual earnings will fall at least $530 million short of expectations, largely because of slowing growth at its First USA subsidiary.

First USA is the nation's second-largest card issuer, after Citibank, and last year it acquired the Giant card along with other cards issued by Chevy Chase Bank.

From the advent of the first successful general-purpose credit card, the BankAmericard, in the late 1950s until very recently, card issuers had focused on attracting new customers and building market share. The business was slow at first, but in the 1980s it exploded, with Americans grabbing up plastic and running up balances, seemingly unfazed by annual interest rates of 18 percent to 24 percent.

Originally, the cards had required the customer to pay an annual fee, generally between $12 and $20, and stores accepting the card had to pay a merchant fee of as much as 5 percent.

But with interest income soaring, issuers started dropping the annual fee to get their plastic into more wallets and purses. And to expand acceptance, they negotiated merchant fees down until now they are in the 1 percent to 2 percent range, sometimes less.

Interest income seemed ample not only to carry the whole system but also to pay for rebates and discounts, leading banks to enter generous deals such as the one involving Giant.

But in the early '90s, the marketplace began to change. Convenience use, the industry term for the practice of paying off credit-card bills every month and avoiding finance charges, began to rise. Just eight years ago, 29 percent of cardholders were convenience users; today it's 42 percent, McKinley said.

Part of this rise was related to rebate-type programs, which attracted customers who had no intention of ever carrying a balance. But a growing number of consumers who had carried long-term balances have been paying them off. Lower interest rates and higher house prices allowed many homeowners to refinance their homes and take cash out to pay off their credit cards. At the same time, consumers came to realize how expensive plastic credit can be.

These developments are bringing issuers up against some hard economic facts, experts say.

It costs banks about $79 to find a new customer, with some banks spending as much as $150, McKinley said. When that new customer takes a low introductory interest rate and then moves on when the rate goes up, there's little gain for the bank.

If the customer stays but pays off every month, it's also tough to make money. And rebates make things even worse.

It costs a bank about $35 a year to maintain an account, sending out bills and new cards. If the only income is the merchant fee, which is often split with the merchant's bank, a customer charging $3,500 a year will yield the issuer around $30. "If you're going to pay them back $35 in rewards, that's not a very good situation" for the bank, McKinley said.

There is much industry interest in dropping very low teaser rates, though so far card issuers seem unable to wean themselves from price cutting. If some issuers drop teaser rates, those that keep them might gain a competitive advantage.

Other revenue enhancers discussed in the industry, such as eliminating grace periods or restoring annual fees, remain more conversation pieces than actual strategies.

A strategy that is being tried--more aggressive imposition of other fees--has generated bad publicity and consumer resistance along with revenue. Some enraged card holders have even gone to court over the fees.

Bank One officials recently conceded that the penalties had caused some card holders to take their business elsewhere, more than offsetting the revenue gain.

An example of that is Stephen Newborn of Washington, a government employee, who had been dropping his Giant Visa payment off at the bank at the last moment and had never had a problem. But after First USA took over, he was quickly hit with a $29 late fee. The bank offered to take it off when he complained, but he said he will simply drop the card.

"I would have kept it if they hadn't done this," he said.

Compounding the growth of convenience use is the rising tide of bankruptcies among card holders with balances. Though delinquencies have improved recently, the industry continues to lobby to tighten bankruptcy laws, so far without success.

"It appears that the market is being pulled in two directions," Givens said, "those of us who are using the cards for convenience, and those going into bankruptcy."

But he's not giving up: He recently ran across a card that will give him cash back on his telephone bill. It looked good, he said, so he's applied.