Less than a week after AAPL stock reached a new high for 2013, and two analysts raised their target price in response to Black Friday sales, the stock has also hit a 52-week high, running at $570 at the point of writing.

Billionaire investor Carl Icahn doubtless played a role, yesterday tweeting that he would be calling for a (non-binding) shareholder vote on an increased buyback program – though for a smaller amount than he had originally urged.

But Fortune yesterday posted a rather interesting chart that may suggest the upward trend will continue … 

What the chart shows is that the recovery so far has been driven mostly by private investors: the institutional investors who made a run for it when the stock price fell haven’t yet returned. UBS’s Steven Milunovich expects this to change.

If he’s correct, the medium-term trend is likely to continue in an upward direction. As ever, however, remember that the market is driven by sentiment, not by facts …