What Is a Round Lot?

What Is a Round Lot?

Let me explain what a round lot is—it's a standard trading order for securities, consisting of 100 units or any multiple of 100. You can trade these lots on exchanges, and they apply to various securities like stocks and bonds. For stocks, think of it as 100 shares or a number evenly divisible by 100. For bonds, it's usually $100,000 worth. We often call this a normal trading unit, and it's different from an odd lot.

How Round Lots Work

In trading, a lot means a fixed number of units of a financial asset that you trade on an exchange. You can buy or sell these lots, and they cover any financial instrument, from stocks and ETFs to bonds, options, futures, and foreign exchange.

Investment managers and institutions buy stocks in large batches like this. Round lots typically have lower trading costs than other orders, and you get discounts for different round lot amounts. They simplify trading and boost market efficiency.

Historically, the smallest order on an exchange was a round lot of 100 shares. But that's evolving. Now, odd lots and even fractional shares let you execute orders as small as one share or less on some exchanges.

Types of Round Lots

For stocks, a round lot is typically 100 shares or a multiple of 100. ETFs trade like stocks, so they follow the same rule.

In bonds, it's usually $100,000 worth or multiples of that. Anything else is an odd lot with higher costs, though the bond market is innovating for smaller trades.

For options, a round lot is 100 contracts in listed calls and puts. You can buy just one contract, which often represents an odd lot of stock. Commodities have their own round lot definitions.

In futures, contract sizes are lots, varying by the underlying asset like commodities, currencies, or interest rates. For example, wheat futures have a lot size of 5,000 bushels.

Forex lots vary too—a standard lot is 100,000 units of the base currency, with micro and mini lots at 1,000 and 10,000 units.

Fast Fact

Round lots generally execute quicker, but trading odd lots is getting easier and less costly.

Round Lots vs. Odd and Mixed Lots

An odd lot is fewer than 100 shares or not evenly divisible by 100. These can be combined into round lots for easier trading. A mixed lot includes both a round lot and an odd lot, like an order for 198 shares.

Odd lots are more common now but often cost more. Electronic trading has cut those extra fees. Still, some exchanges prioritize round lots for certain orders, like reserve orders at specific prices.

You can even trade fractional shares now, starting from dividend reinvestment. Many brokerages use this for dollar-cost averaging, where you invest a fixed amount monthly in a stock or fund, ignoring price changes.

What Is a Round Lot Holder?

A round lot holder owns a round lot of unrestricted shares— that's 100 shares or a multiple. Unrestricted means no conditions before transferring or selling them.

What Is a Board Lot?

A board lot is the standard number of share units set by an exchange as a trading unit. It's usually the same as a round lot—100 shares or multiples. But it can vary by exchange; for example, Japanese exchanges use 1,000 shares.

Are Round Lots More Common Than Odd Lots?

Round lots are common for large orders because they have the lowest fees. But odd lots are growing among traders and brokers, thanks to automated trading making them easier and cheaper.

The Bottom Line

A lot is the total units of a financial instrument traded on an exchange—they can be mixed, odd, or round. The exchange sets the round lot size, often 100 shares or multiples for securities like stocks or bonds. Trading in round lots improves efficiency and cuts costs as bulk orders.