Portfolio Pumping
The illegal act of bidding up the value of a fund's holdings right before the end of a quarter, when the fund's performance is measured. This is done by placing a large number of orders on existing holdings, which drives up the value of the fund. Also known as "marking the close".
Investopedia Commentary
This can be highly destructive for investors in the fund as it is a temporary gain and the stocks will generally fall back to previous levels once the price manipulation is over. For example, if a fund had 1,000 shares of ABC, purchased for $10 per share, but if the shares are trading at $9 right before the managers’ performance is measured, they will have performed poorly. As a result, they may resort to portfolio pumping by placing enough orders to bid the price to $14, which dramatically increases the fund's performance. However, it is likely that the shares will fall back towards $9, leaving investors with a $9 stock that was made to look like a $14 stock.
Related Links
The Short And Distort - Stock Manipulation In A Bear Market
Investment Scams Tutorial
See also: Bid, Fund Manager, Mutual Fund, Overvalued, Pump and Dump, Securities & Exchange Commission - SEC
portfolio pumping