I doubt Apple will want cash reserves that high. Investors criticize companies that have too much cash and just sit on it, ie microsoft and now apple.
The reason is the company should be using some of that cash to invest in growth opportunities or their future, either acquisitions, R&D or new projects. If they don't do anything with the cash and just sits on it, this action is a signaling mechanism that essentially says that Apple doesn't see any growth opportunity worth investing in. Traders will sell the stock because there is no recognizble opportunity to grow revenue and they are not investing in their future so they can be vulnerable to competition in the future.
The reason is the company should be using some of that cash to invest in growth opportunities or their future, either acquisitions, R&D or new projects. If they don't do anything with the cash and just sits on it, this action is a signaling mechanism that essentially says that Apple doesn't see any growth opportunity worth investing in. Traders will sell the stock because there is no recognizble opportunity to grow revenue and they are not investing in their future so they can be vulnerable to competition in the future.