Few hedge fund managers garner the type of attention that David Einhorn does just by opening his mouth. The Greenlight Capital manager's name has even become a verb. No investor wants his stocks to get "Einhorned," which is what happens when Einhorn takes a publicly bearish stance against a company, typically preceded by a short position.

Einhorn also has no qualms about criticizing companies that he's bullish on and has sizable stakes in, famously bashing Microsoft (MSFT 0.77%) CEO Steve Ballmer in 2011. Just Einhorn's suggestion that Ballmer should step down sparked a rally. A few months ago, Einhorn also launched a legal assault on Apple (AAPL -1.67%) over its capital allocation policy, even though the Mac maker remains one of his top picks.

Well, Einhorn just dumped a major chunk of his Microsoft position while loading up on Apple in the first quarter. Greenlight has filed its most recent 13F disclosure, which can be compared with the previous one.

Position

Q4 2012 Shares

Q1 2013 Shares

Difference

Microsoft

10.8 million

6.1 million

4.75 million sold

Apple

1.3 million

2.4 million

1.1 million bought

Source: SEC filings. Figures may not sum due to rounding.

Those figures translate into a 44% reduction in Greenlight's Microsoft position, accompanied by an 84% boost in the Apple bet, not including the call options that he was holding at the end of Q4.

We can't know for sure at what prices these trades took place, but Einhorn has partially missed out on Microsoft's major rally this quarter that was sparked in April by ValueAct taking a nearly $2 billion position. Apple, on the other hand, is down marginally quarter to date.

Company

Quarter-to-Date Performance Through Yesterday's Close

Microsoft

19%

Apple

(1.8%)

 Source: Nasdaq.

So far, Einhorn's move has been mistimed, but we're only talking about six weeks of performance. The switch hasn't paid off yet.