U.S. Markets close in 5 hrs 2 mins

Warren Buffett's bad week: $2.5B lost on two stocks

Ben Berkowitz
Adam Jeffery | CNBC

Warren Buffett is happy to admit his mistakes when he makes them-just don't remind him how much money he lost in the process.

IBM and Coke represent two of Berkshire Hathaway's (BRK-A) three biggest investments, but their operational missteps have already cost him $2.52 billion this week (factoring in Wednesday's early declines).

On Monday, Buffett lost nearly $1 billion on his third-largest investment, IBM (IBM), after the company posted disappointing earnings.

On Tuesday, Coca-Cola (KO) did the same thing , posting third-quarter revenue that fell short of expectations and warning of currency headwinds.

The losses in IBM and Coke add to a recent rough patch for Buffett, who slashed Berkshire Hathaway's (BRK-A) stake in British grocer Tesco (London Stock Exchange: TSCO-GB) earlier this month.

Read More Buffett on stocks: Look at them as businesses

He has described buying into the stock as a "huge mistake."

And to be sure, it hasn't been all bad news this week-Buffett's favorite bank, Wells Fargo (WFC), is up more than $816 million since Monday morning.