Warren Buffett just lost ANOTHER $1B on this

Spare a thought for Warren Buffett, whose portfolio is not doing him any favors this week.

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

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

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Coke is Buffett's second-largest investment and has been one of the stalwarts of his portfolio for decades. (He left Coke's board in 2006 and his son Howard took a board seat there in 2010.)

With 400 million shares, Tuesday's decline of $2.72 cost the Oracle of Omaha $1.09 billion. Shares were on track for their worst day since October 2008. (With IBM's $7 decline on Tuesday, he was out another $494 million there, too).

"I love Coke. I love the management, I love the directors," Buffett said in a CNBC interview in April, while discussing the recent controversy over the company's executive pay plan.

The losses in IBM and Coke add to a recent rough patch for Buffett, who slashed Berkshire Hathaway's stake in British grocer Tesco earlier this month.

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