No one is sure how, and no one is sure why, but the Public Employees Insurance Agency was $52.9 million under budget through May.
Most of that surplus was caused by a dramatic drop in health care claims.
While PEIA budgeted for $367.8 million in medical expense claims through May, members submitted only $325 million in claims. That's a savings of $42.8 million.
Prescription drug expenses are also down. PEIA budgeted $115.6 million for drug claims through May but paid out only $108 million.
Chief Financial Officer Jason Haught told PEIA finance board members on Thursday he is not sure why the expenses are coming in so far under budget.
"You might want to keep record of this because it's likely the last time you'll see that happen as a board member," he said. "Eleven months in, and I'm still not used to it."
Haught said he expects the trend to continue through June 30, the end of the 2013 fiscal year. Financial numbers for June will be presented at the board's September meeting.
PEIA actuary Dave Bond said the agency would begin its annual trend analysis for 2013 in a few weeks and hopes to uncover the cause of the budget surplus.
"There's been some assumptions it's due to the sluggish economy," Haught said.
Members could be putting off unnecessary medical services in an attempt to save money.
The state's Retiree Benefit Trust Fund also is performing significantly better than expected.