Actually the drop makes it a little safer to buy before earnings... relatively speaking. As a rule I rarely hold anything into earnings, because many stocks drop even on good earnings, and of course on bad they drop too. That said, this is a relatively easy company to analyze without a lot of moving parts. If assets under management rise, their fees rise and earnings rise. With 4 of the top 5 mutual funds (amazing) in the industry and knowing how the sheep chase past returns you can bet their AUM are rising and their fees are rising. If the stock had continued its sharp rise of the previous 2 days into earnings it would of been a lot more of a crap shoot because say the stock had rallied 20-25% in the 3 days going into earnings, than what? Do you expect another 10% even if the earnings are blowout?
Now with this drop a 10% rise from here (after a solid quarter) puts it basically where it opened today... so lots of risk is taken away, and potential for upside increased.
With all that said there is still a *CHANCE* of a miss (nothing is certain in investing) but this sort of crazy manipulation ahead of earnings has all the markings of a stock driven down to get big money in ahead of earnings... thats just me from watching this stuff for 10+ years, and seeing this pattern in the past. Occassionally it means a big earnings miss and a leak out from someone inside the company, but usually its just the big players playing their games and as little fish (lamprey as I like to call myself) I just like to latch onto the sharks and let them do the work. All that said, as I said, I usually don't hold anything into earnings but am making an exception here, and hope it doesn't backfire ;)