The agency's finances have been severely strained in the last three years by a string of large pension defaults, mostly in the airline and steel industries.

The settlement appeared to compensate the pension agency at a somewhat higher level than is typical in cases of pension default.

The pension defaults last year of just three steel companies erased $7 billion of the agency's surplus.

That move led to the largest pension default in the three decades that the government has guaranteed pensions.

Analysts said yesterday that the pension default might put pressure on United's rivals, like Northwest and American, to reduce the costs of their retirement plans.

Consider United's plan for its pilots, the employees with the richest benefits and consequently the most to lose in a pension default.

The most important mission of pension reform is to protect employees from being shortchanged and taxpayers from having to foot the bill for pension defaults.

Mr. Ehrhardt said the pension deficits underscored by the survey were not a sign of any impending pension defaults by the companies.

United's employees - particularly its pilots - would also be subject to big losses in the event of a pension default.

Bankruptcy is often a prelude to a pension default.