Liquidity Risk
Liquidity is defined as the ability to sell a quantity
of a security without adversely changing the price in response to one's orders. Models for liquidity risk are not as common place as models for market risk. One simple precautionary measure that practitioners use to control liquidity risk is to measure the size of their trades versus the average daily trading volume of a security. A rule-of-thumb is to not hold positions greater than 1/10-1/3 of the average daily trading volume over some specified time interval, such as the last 30 days of trading.