Apple (AAPL) announced its quarterly earnings Tuesday, and -- big surprise -- they were stellar. But one of the numbers not discussed much in analysis of its results was the more than $76 billion Apple holds on its balance sheet. This includes $12.1 billion in cash and cash equivalents, $16.3 billion in marketable securities, and $47.8 billion in long-term marketable securities. More remarkable still is that, based on Apple's earnings, that figure could reach $100 billion by year's end -- after all, the upcoming two quarters include back-to-school and the holiday season.

What Apple will do with all of that money has been discussed for two or three years as the balance has grown. Apple has made few acquisitions of any size. Its stock rose to near $400 after it released results. With a market cap in excess of $360 billion, it could easily use its stock as currency if it wanted to purchase of another large company.

But which company? There seem to be few appropriate targets. Apple doesn't need to buy another handset or PC maker. It's too successful to buy competitors who already do poorly compared to it. Apple can hardly buy its major rival, Google (GOOG), which has a market value of $195 billion. There might be some value in capturing its search business, and the Android mobile OS which is Apple's only real competitor in that arena -- but Apple has already stated publicly that it does not want to be in the search business. Other fast-growing Internet companies like Facebook, Groupon, or Twitter wouldn't seem to be of any use to Apple.

Apple has enough power with investors to ward off any pressure to distribute the cash to shareholders. It can argue that its stock is up nearly 60% in the last year. What more could investors want?

Every time the company releases its quarterly earnings, the press and Wall Street will continue to ask what Apple will do with its ever growing stash of cash. And Apple will continue to deflect the question and leave everyone guessing.