Winners & losers in financial services this week:

Winner

Forget about the 64% first-quarter earnings decline Berkshire Hathaway (BRK.A) (BRK.B) reported last week. (It came about mainly from derivatives writedowns that should reverse between now and expiration.) Warren Buffett seems to be enjoying himself a lot during this credit crackup.

According to press reports out of Omaha during Berkshire's annual-meeting weekend, Berkshire a) has bought some subprime mortgage portfolios via its Clayton Homes unit, b) is looking at RBS's insurance business, c) is close to a separate mid-sized acquisition in the UK, d) has spent some time looking at the investment banks, e) made a fair amount of money during the disruption the auction-preferred market, and f) wrote $400 million in bond insurance premiums during the first quarter, more than anyone else in the business.

Wow, we're running out of alphabet. Wailing and gnashing of teeth in the face of upheaval this is not. . P.S. About the only thing Buffett seems not constructive on is Berkshire stock itself. . .

Loser

Deutsche Bank (DB) CEO Josef Ackermann blames DB's $4.2 billion first-quarter writedown, as well as its first quarterly loss since 2003, on "financial market conditions [that] "were the most difficult in recent memory."

Tom Brown is head of BankStocks.com.