TIGARD — The board in charge of the Oregon College Savings Plan has decided to withdraw from a poorly performing fund responsible for steep investment losses.

At a meeting of the Oregon 529 College Savings Board on Thursday, board members said continuing with the fund was not in the best interest of investors. They voted to move those dollars into an index fund, which tracks the market and should be more stable.

Overall, the College Savings Plan has lost about 25 percent of it worth in the past few months, but the piece receiving the most attention is the Oppenheimer Core Bond Fund, which lost 38 percent of its value when comparable funds posted a gain of about 4 percent.

That decline led to a 9 percent drop overall in the plan’s most conservative option, marketed toward thousands of families with children in college or about to start.

“Our great responsibility is going forward,” said state Treasurer Ben Westlund, who chairs the board. “How do we make this plan work?”

Kurt Wolfgruber, chief investment officer for OppenheimerFunds, defended the group’s handling of the Core Bond Fund and said it was managed within the guidelines set for it. Before 2008, he said, the fund had never lost money on a yearly basis.

The problem, he said, was that much of the market upheaval was unprecedented and steps taken to shore up the fund — such as investing in high quality securities — actually worked against it.

“We were, essentially, for all the right reasons, in the wrong places,” he told the board.

A separate review of the fund by investment firm Arnerich Massena, commissioned by the board, seemed to bear this out.

Daniel Block, one of the reviewers, said OppenheimerFunds wasn’t the only group to turn to high quality securities when the market first showed signs of weakening.

“It’s not an excuse, but they’re not alone. A lot of people, a lot of extremely smart people, got hit, too,” he said. “We have no fault with the investments the team chose to do.”

Block also noted that the fund’s manager had resigned and been replaced, and that a new team was being constructed to manage it.

The new manager, added Chris Abbruzzesse, another man involved in the review, had gone a long way to assure them that industry best practices would be used in the future.

Still, the group found that the new management “adds a little bit of uncertainty to the product.”