Odd Lot

An odd lot is a stock order for fewer than 100 shares, which is the standard "round lot" size. Historically, odd lots were more expensive to trade due to additional handling fees and were sometimes viewed as a contrarian indicator (the "odd-lot theory" suggested that small investors were usually wrong at market extremes). However, the significance of odd lots has evolved dramatically with the rise of commission-free trading, fractional shares, and high stock prices. When a single share of Berkshire Hathaway Class A costs over $600,000 or Amazon trades above $180, most retail investors necessarily trade in odd lots. Today, odd-lot trading represents over 50% of all stock transactions by count. Exchanges have adapted their rules to provide better execution quality for odd lots, and the distinction between odd lots and round lots has become largely historical for retail investors.