48 days after declaring a 7:1 split, Apple is up 25% by Philip Elmer-DeWitt @FortuneMagazine June 11, 2014, 7:23 AM EDT E-mail Tweet Facebook Google Plus Linkedin Share icons Did Apple just pull a reverse Warren Buffett? Buffett, whose Berkshire Hathaway brk.a trades in six figures, famously wrote that he had no interest in a stock split that would replace his “clear thinking” shareholders with more impressionable ones who “feel wealthier with nine $10 bills than with one $100 bill.” Steve Jobs always said he agreed with Buffett. A stock split, mathematically, does nothing. With Apple AAPL up 25% since April 23, the day the 7:1 stock split was announced, it clearly does something. But maybe not for the reasons you hear on CNBC. The two leading theories for why Apple split its stock are… – Liquidity: By making its shares more affordable, the company made it easier for more people to buy and sell it. – A spot in the DOW 30: At $700 a share, Apple would have been the tail that wagged the Dow. Taking the second theory first, it’s hard to see Apple itching to get into DJIA. Apple prefers to think of itself as a scrappy start-up, not a stodgy Dow 30 component like Caterpillar CAT , Exxon XOM or Wal-Mart WMT . On the other hand, by making the stock easier to buy, Apple may have turned Buffett’s argument on its head. Splitting Apple 7 for 1 instantly made it more attractive to retail investors — people who look at the share price and say “hey, now I can afford 100 shares of Apple!” But it also made it less attractive to hedge funds, high-frequency traders and institutional investors — the “clear thinking” class unlikely to be swayed by psychological effects. These are the folks whose algorithms buy and sell weekly stock options at the speed of light. They may not be swayed by a trick of arithmetic, but they are swayed by trading costs. And the more shares they have to trade, the higher those costs. It’s too early to say whether the class of investors attracted to Apple has changed in a material way. But it’s possible what we’re seeing now is how Apple is supposed to trade. Not as a vehicle for gaming weekly option expirations, but as a stock. See also: Is Apple ripe for a stock split?