NEW YORK (CNN/Money) - Low and zero-interest rate loan offers from automakers are getting more attractive without changing at all, due to the rising interest rates available on other lenders' car loans.

The automakers appear likely to stick with the current widespread zero-interest financing offers even as the Federal Reserve and the financial markets raise interest rates in the coming months.

Independent lenders such as banks, thrifts and credit unions have already raised rates by about two-tenths of a percentage point in the last three months, according to interest rate tracker Bankrate.com. The Fed is widely expected to raise its benchmark interest rate by a quarter percentage point on June 30.

As recently as five years ago, bank auto rates would have risen in sync with a Fed hike. Now, with more selling their auto loans on the secondary market, auto loan rates now move ahead of the Fed action, said Greg McBride, senior financial analyst for Bankrate.com.

And, since the June 30 boost is seen as only the first in a series of Fed moves, McBride says banks' car loan rates are clearly heading higher the rest of this year.

"We'll continue to see some movement in response to anticipation of future Fed rate hikes," said McBride.

Meanwhile, auto company officials say it's unlikely they'll pull back on zero- or low-interest incentives -- especially heading into their summer clearance period, when they need to move out the 2004 models to make room for new 2005 models. And that means those financing packages are worth a second look.

But even with rising auto finance rates, it might still make sense to take an automaker's cash-back offer rather than the zero-percent financing, especially on less expensive cars.

For example if a buyer can get $3,000 back on a $15,000 car, like the Chevrolet Cavalier, and then put $1,000 down, the car payments are going to be about $220 a month even at a 7.5 percent interest rate.

If the buyer uses zero-interest financing and puts down the same $1,000 in cash, the payments to borrow $14,000 interest-free over five years comes to $233 a month.

And the 7.5 percent rate is probably still on the high side for a bank auto loan, said McBride.

"That's the average rate, but if you do the comparison shopping, you can still find rates under the 6 percent," he said.

Financing $11,000 at 6 percent brings the example payment down to $212 a month.

With more expensive cars, the zero-interest offers are likely to be the more attractive option, said Paul Calisi, administrator of the AAA car buying service, which often compares the value of the different kind of incentive offers for potential buyers. That wasn't the case when bank rates as low as 5 percent could be found a few months ago.

"You have to do the analysis in each case, but without question it makes more sense to take the low rates from the captive finance arms today (than it did in the past)," said Calisi.

Paul Ballew, executive director of market and industry analysis for General Motors Corp., which has been setting the industry lead on incentives used to lure buyers, said GM is now seeing about 30 percent of buyers taking advantage of incentive financing offers,.

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But he could see that rate rising to about 40 percent this summer as market rates continue to rise.

"We may see the consumers jumping back in (to low-interest finance deals)," he said, saying the percentage will depend on how fast rates rise.

As for what offering zero percent financing costs automakers, Ballew figures that each percentage point rise in other bank rates translates to a couple hundred dollars per vehicle. With more than 1.5 million U.S. vehicles financed each year, that translates into hundreds of millions of added costs to the world's largest automaker as rates rise.

"We'll keep our options open," Ballew said. "The good news for us is we've been anticipating the fed would move for a long time. We knew these were abnormally low rates."