WASHINGTON -

A federal watchdog agency warns that despite an improving U.S. economy, retirement plans covering roughly 1.5 million workers are severely underfunded, threatening benefit cuts for current and future retirees.
    
The Pension Benefit Guaranty Corporation says multi-employer plans, which are collectively bargained retirement plans maintained by more than one employer, are most at risk.
    
At the same time, the agency says single-employer pension plans - covering a little more than 30 million participants - are on firmer financial footing and are likely to remain so at least over the next 10 years.
    
The report says as shaky as the situation is for underfunded multi-employer plans, the outlook is slightly better than it was just a year ago as the nation's economy gradually improves from the severe 2007-2009 recession.