Mmm, pulverized stock...Talk about swooping in to pick up value. Constellation Energy, which has been hammered this week, losing 58% of its value in just three days, is being purchased by MidAmerican Energy Holdings Co., which is owned by — go figure — Warren Buffet’s Berkshire Hathaway.

It’s nice to have a couple of billion dollars lying around,” says one market strategist.

The deal is for $26.50 a share, or about $4.7 billion. That’s less than half of what the company was worth before the beginning of the week, when investors deserted the stock amid concerns about the utility’s exposure to Lehman Brothers Holdings (two subsidiaries are counterparties with Lehman units), as well as its capital needs.

But the firm’s exposure to various financial institutions amounts to just $120 million in the form of coal, utilities and power-related contracts, and the hammering of the stock provided an opening for Mr. Buffett.

Never mind those capital needs. CEG shares are were up 3.4% in premarket trading to $25.60 a share. “MidAmerican has been a wonderful steward of its energy assets and the acquisition of Constellation Energy, when completed, will prove beneficial to all constituents,” said Mr. Buffett, chairman of Berkshire Hathaway, in a statement.