With shares of Apple ( AAPL) trading near an all-time high, CFO Peter Oppenheimer decided it was time to cash in. Oppenheimer exercised 750,000 options last week, grossing a cool $32 million. And he's only the latest Apple executive to take advantage of the stock's latest bull run. In recent months, at least four other senior company executives have cashed in 100,000 or more options, seeing millions of dollars' worth of gains. The sales by Oppenheimer in particular could be something of a red flag, says Jonathan Moreland, director of research at InsiderInsights.com. It's not uncommon to see insiders exercise their options after a stock's had a strong run, but what's unusual is that Oppenheimer's sales have come in one big burst of activity, he says. "The question arises, 'Why now?'" says Moreland, a contributor to TheStreet.com's sister site, RealMoney.com, who has no position in Apple. But other analysts were less concerned. With Apple having performed so well in the last two years, many investors are likely to overlook some insider sales, says Todd Fernandez, a researcher at Glass Lewis, a proxy analysis and stock research firm. "I don't see this as a red flag," says Fernandez. "These guys get a hall pass for a little bit of time." Apple spokesman Steve Dowling declined to discuss Oppenheimer's reasons for selling. "It's great to see our management team get rewarded for their incredibly hard work by selling some of their stock," he said. The sales by Oppenheimer and the other Apple executives are governed by 105b-1 trading plans, which typically state how many shares an executive plans to sell and give guidelines on when those shares will be sold. But Apple has not disclosed the details of the trading plans, and Dowling declined to divulge them.