With naked short-selling, a trader has almost limitless ability to hammer a stock into the ground.

FORBES

Trade settlement failures can be an indication that a manipulative form of short-selling--called naked short-selling--is going on with the stock.

FORBES: More Shots Fired In The Shorting War

In the past, the agency has been flooded with letters from ordinary investors begging it to put a stop to naked short-selling.

FORBES: Naked Short-Selling