Liquidity
A security's liquidity is how easily it can be bought or sold without moving its price. It shows up in traded volume and above all in the spread, the gap between the best bid and the best offer at any moment. It is an invisible cost that appears in no commission line: in a thin stock, getting in and out can cost several tenths of a percent before the price has moved a cent. And it is a risk as well as a cost, because liquidity tends to vanish exactly when it is most needed, in falling markets.
See also
See it on real data
Celsmar computes this from the accounts companies file with their regulator, and shows which line every figure comes from. Free to start, no card.
Definition for informational purposes. It is not financial advice nor a recommendation to buy or sell.