For some workers, depending on their tax bracket and insurance costs, the new tax credits would exceed the value of the tax exclusion, making the swap profitable. But with the average employer-sponsored family policy costing $12,680 this year, other workers would find the exchange a losing proposition. They would either have to spend more, reduce their coverage or persuade employers to make up the difference.

Officials with eight business trade groups contacted by The New York Times predicted the McCain plan would raise costs and force some employers to stop providing health benefits.

A recent survey of 187 corporate executives by the American Benefits Council and Miller & Chevalier, a con...

For some workers, depending on their tax bracket and insurance costs, the new tax credits would exceed the value of the tax exclusion, making the swap profitable. But with the average employer-sponsored family policy costing $12,680 this year, other workers would find the exchange a losing proposition. They would either have to spend more, reduce their coverage or persuade employers to make up the difference.

Officials with eight business trade groups contacted by The New York Times predicted the McCain plan would raise costs and force some employers to stop providing health benefits.

A recent survey of 187 corporate executives by the American Benefits Council and Miller & Chevalier, a consulting firm, found that three-fourths felt the repeal of the tax exclusion would have a “strong negative impact” on their workers. Only 4 percent said they would provide additional pay to fill any gaps.

John J. Castellani, president of the Business Roundtable, an association of leading chief executive officers, said his group instead supported extending the tax exclusion to those who bought coverage on their own.

“One of the things we don’t want to do,” Mr. Castellani said, “is jeopardize 170 million Americans who do get insurance through their employers.”