EJ
I think funds will buy small quantities of what they are holding at the end of the year in order to massage their books slightly. I once knocked £1m off the market cap of a company by trying to sell £1000 worth of shares and the MMs marking the price down. In the same way, a fund could buy a few grands worth of a share they hold and add hundreds of thousands of pounds to the value of the fund.
If a fund manager does that on a year when the markets have risen anyway, his end-of-year performance based bonus might be quite good.