Yahoo – One of the most popular trading ideas among tech funds is to short BlackBerry — more than 30% of its stock was sold short recently. And another very popular idea has been going long on Apple, of course. As we all know, those two trading strategies went tragically awry last winter, when Apple’s share price plummeted from $700 to $400 and BlackBerry’s stock spiked from $6 to $18. This helped demolish the performances of many of the best known tech funds on Wall Street in the fourth quarter last year and the first quarter in 2013. But that’s not the interesting part. The interesting part is that the weird winter trends seemed to have reversed in the spring and many funds flocked back to shorting BlackBerry shares and going long Apple…. only to see a counter-reversal taking place.