What is defined as an odd lot in securities trading?

An odd lot in securities trading refers to an order that is placed for a quantity of shares that is less than the standard trading unit, which is typically 100 shares. In this context, since the definition focuses on quantities that deviate from the norm of 100 shares, an order for less than 100 shares qualifies as an odd lot. This distinguishes it from round lots, which are orders of 100 shares or more.

Typically, trades involving odd lots may not have the same liquidity or transaction efficiency as round lots, which can affect pricing and execution. Understanding this concept is essential for recognizing how orders may be handled differently in the market.