What if the cash reserves are for a stock buyback?

Apple currently has cash reserves of about $137B (which by all indications will keep on rising), and a market cap of $438B. Thus, at the current valuation, they have enough money to buy about 31% of themselves. What I'm suggesting is, what if they're saving up to purchase at least 51%?

The market has not been nice to Apple lately. Despite strong quarter after strong quarter, pundits keep forecasting their fall, and these forecasts manifest themselves in the performance of the stock. By cutting investors out of the picture, Apple could just focus on selling stuff and being profitable rather than having to worry about what the market thinks.

The idea is a bit far-fetched, but I was wondering what you guys think.