The situation at U.S. defined benefit and defined contribution retirement plans may have deteriorated sharply in just 6 months.

Researchers at the International Foundation of Employee Benefit Plans, Brookfield, Wis., have come to that conclusion in a summary of results from a May survey of 1,305 large and midsize U.S. pension plan sponsors.

The percentage of defined benefit plan sponsors who said their plans have made major asset-allocation changes has increased to 42% this month, from 20% in late 2008, the IFEBP researchers report.

About 37% of the sponsors that made changes have increased allocations to fixed-income investments.

About 16% of participants at defined contribution plan sponsors say the sponsors have reduced or eliminated employer matches as a result of the recession.

At companies that have changed the match, 44% have reduced the amount of the match and 52% have eliminated the match, IFEBP researchers say.

Decreases in participant contributions now are affecting 44% of the participants’ defined contribution plans, up from 28% in late 2008.

Over that same period, the percentage of defined contribution plans seeing more hardship withdrawals increased to 42%, from 29%.