While it’s now more than two-and-a-half years since the collapse of Lehman Brothers and the worst of the financial crisis, several top investors are still avoiding bank stocks.

“We find it hard to believe the banks have cured all their bad asset problems, and they aren’t transparent enough for us to understand the risks,” Clyde McGregor, whose Oakmark Equity and Income Fund has beaten 99% of peers over the past decade, tells Bloomberg. “Can you still make money in banks? Maybe. But we can build a portfolio that doesn’t demand owning them.” McGregor says a big part of the problem is derivatives, whose complexity and dependence on a multitude of hard-to-predict factors make them difficult to value.

Donald Yacktman, who has also compiled an excellent long-term fund-management track record, is also leery of banks, and held only one bank stock at the end of the first quarter, according to Bloomberg. “With a bank you create assets with a stroke of a pen,” Yacktman said. “You’ve got a black box.”

Another top fund manager, John Delafield, whose fund ranks number one among mid-cap value funds over the past decade, agrees. “It’s impossible from the outside to know the value of what they hold,” he told Bloomberg. Delafield’s fund had 30% of its money in industrial stocks, 28% in basic materials and none in financials as of March 31, according to Morningstar data.

On the other side of the debate is Bruce Berkowitz, one of Morningstar’s fund managers of the decade. He has more than two-thirds of his fund’s equity in financial stocks, according to Bloomberg, with holdings that include Citigroup and Bank of America. “The balance sheets look better than ever, the banks are making money and they are dealing with their issues,” he said.