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What is a 'Lot (Securities Trading)'

A lot is the standard number of units in a trading security. In the financial markets, a lot represents the standardized quantity of a financial instrument as set out by an exchange or similar regulatory body.

BREAKING DOWN 'Lot (Securities Trading)'

When investors and traders purchase and sell financial instruments in the capital markets, they do so with lots. A lot is a fixed quantity of units and depends on the financial security traded.

For stocks, a lot is the number of shares that is purchased or sold in one transaction. The standard minimum stock order that can be placed through an exchange without incurring higher commission fees is 100. In the stock market a lot of 100 shares is known as a round lot. A round lot can also refer to a number of shares that can evenly be divided by 100 e.g. 300, 1200, 15500 shares, etc. Trading with odd lots, that is less than 100 shares or a number of shares not divisible by 100, commanded higher commission costs in the past. However, the emergence of electronic and online trading platforms has reduced or eliminated the premium paid for trading in odd lots.

An investor who puts in an order to purchase, say 370 shares of a company’s stock is trading in a mixed lot – round lot and odd lot. In this case, his order will be broken into two separate orders comprising of one 300 round lot and one 70 odd lot. His order will be filled in two sections as well so when he checks his order status on his trading dashboard, he will see 300 shares filled at a certain price and another section that has 70 shares filled at a certain price. The prices at which each lot is filled may be the same or different, depending on the liquidity for the stock.


Similar to stocks, the board lot for exchange-traded securities, such as an exchange-traded fund (ETF), is 100 shares. For example, if the iShares North American Tech (IGV) ETF was trading for $148, based on the board lot of 100 shares, an investor will put in $14,800 as a minimum investment, excluding brokerage commissions.


The bond market is dominated by institutional investors who buy debt from bond issuers in large sums. The standard trading unit or lot for a US government bond is $1 million. The municipal bond market has the smallest lot per trade at $100,000. Any bond purchase of less than the standard lot is referred to as an odd lot.


In terms of options, a lot represents the number of contracts contained in one derivative security. One equity option contract represents 100 underlying shares of a company’s stock. In other words, the lot for one options contract is 100 shares. For example, an options trader purchased one Bank of America (BAC) call option last month. The option has a strike price of $24.50 and expires this month. If the options holder exercises his call option today when the underlying stock, BAC, is trading at $26.15, he can purchase 100 shares of BAC at the strike price of $24.50. One option contract gives him the right to purchase the lot of 100 shares at the agreed strike price. With such standardization, investors always know exactly how many units they are buying with each contract and can easily assess what price per unit they are paying. Without such standardization, valuing and trading options would be needlessly cumbersome and time consuming.


When it comes to the futures market, lots are known as contract sizes. The underlying asset of one futures contract could be an equity, a bond, interest rates, commodity, index, currency, etc. Therefore, the contract lots vary depending on the type of contract that is traded. For example, one futures contract for corn, soybeans, wheat, or oats has a lot size of 5,000 bushels of the commodity. The lot unit for one Canadian dollar futures contract is 100,000 CAD, one British pound contract is 62,500 GBP, one Japanese yen contract is 12,500,00 JPY, and one Euro futures contract is 125,000 EUR.

Unlike stocks, bonds, and ETFs in which odd lots can be purchased, the standard contract sizes for options and futures are fixed and non-negotiable. However, derivatives traders purchasing and selling forward contracts can customize the contract or lot size of these contracts, since forwards are non-standardized contracts that are shaped by the parties involved.

Standardized lots are set by an exchange and allows for greater liquidity in the financial markets. With increased liquidity comes reduced spreads in the market, creating an efficient process for all participants involved. For example, it is easier for a broker to match a seller with 100 shares of a stock to a buyer who wants to purchase a round lot, than it is to find a seller for a buyer who wants to purchase 53 shares.

  1. Odd Lot

    An odd lot is an order amount for a security that is less than ...
  2. Mixed Lot

    A mixed lot is a type of order for a number of securities that ...
  3. Even Lot

    A normal unit of trading for securities or bonds. An even lot ...
  4. Tax Lot Accounting

    Tax lot accounting is a record keeping technique that traces ...
  5. Board Lot

    A board lot is a standardized number of shares offered as a trading ...
  6. Job Lot

    A job lot is a futures contract with a commodities trading volume ...
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