DEFINITION of 'Bid Whacker'
A slang term for an investor who sells shares at or below the bid price. This is considered outside the norm, as sellers normally settle for a price between the bid and ask quotes.
BREAKING DOWN 'Bid Whacker'
The person is said to "whack the bid down", since selling at or below the bid will usually lower future bids. Bid whacking usually perturbs other sellers, since it may temporarily drive down the market price of a security.