What is Liquidity?
How easily an asset can be bought or sold without moving its price.
Formal Definition
Liquidity describes the ease of converting an asset to cash at a fair price, reflected in trading volume and the bid-ask spread. Highly liquid stocks like S&P 500 large caps trade in size with minimal price impact, while illiquid securities can move sharply on small orders and are costlier to exit, especially during market stress.
In Simple Terms
It is how quickly you can sell something for cash without having to slash the price. Big, popular stocks are highly liquid; obscure ones can be hard to unload without taking a hit.
Example
A mega-cap like Apple trades tens of millions of shares daily, so a large order barely moves the price, unlike a thinly traded small-cap.