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Markets and Trading

Bid-Ask Spread

The difference between the best posted bid price and the best posted ask price for a security at any moment.

Definition

The bid-ask spread is the most visible component of transaction cost for exchange-traded securities. The bid is the highest price a buyer is willing to pay; the ask (or offer) is the lowest price a seller is willing to accept. A client who buys at the ask and immediately sells at the bid faces an immediate mark-to-market loss equal to the spread. For highly liquid large-cap TSX stocks, the spread may be as narrow as one tick ($0.01); for thinly traded small-cap stocks or ETFs tracking illiquid underlying markets, the spread can be several percent of the price. Under UMIR 5.1 and the best-execution obligation, dealers must consider the bid-ask spread as part of total transaction cost when routing orders. Spreads widen during market stress, at the open and close of trading, and ahead of material news announcements. For ETFs, the bid-ask spread in the secondary market is directly influenced by the spread of the underlying basket and the authorized participant's hedging cost.

Source

UMIR 5.1; CIRO IDPC Rule 3600 series; NI 23-101

Where this shows up on the CIRE

  • Outcome 8.1

Test yourself

Two real CIRE-bank questions on this exact outcome. Click to reveal the answer and the rule citation.

  1. 1

    A mining company executive knows that an internal assay report confirming a major ore discovery has not yet been publicly released. She calls her registrant and places a large buy order in the company's shares. Under Canadian securities law, which of the following is most accurate?

    Outcome 8.1 · click for answer

    A.The trade is permissible because the executive's account is at an arm's-length dealer and the order was placed verbally.
    B.The executive is trading on material non-public information and the trade is prohibited under insider trading provisions of applicable securities legislation; the registrant who knowingly facilitates such a trade may also face liability.Correct
    C.The prohibition applies only if the executive is a director or officer of a reporting issuer; a senior employee does not qualify as an insider.
    D.The trade is permissible because the executive is buying, not selling, her own company's shares.

    Insider trading prohibitions under provincial securities legislation apply to any person in a special relationship with a reporting issuer who trades with knowledge of a material fact or material change that has not been generally disclosed. Senior employees such as executives fall squarely within this definition. The prohibition applies equally to purchases and sales. A registrant who knowingly facilitates insider trading may be found to have tipped or assisted the insider, attracting their own regulatory and civil liability.

  2. 2

    A client buys one call option on shares of a Canadian bank with a strike price of $130 and an expiry of three months. The current share price is $128. Which statement correctly describes the client's position at expiry if the shares are trading at $125?

    Outcome 8.1 · click for answer

    A.The call option expires worthless because the market price ($125) is below the strike price ($130); the client's maximum loss is the premium paid for the option.Correct
    B.The client must buy shares at $130 because a call obligates the buyer to purchase.
    C.The client's call is in the money and they will receive $5 per share.
    D.The option converts to shares automatically because it is an American-style option.

    A call option gives the holder the right; not the obligation; to buy the underlying at the strike price. At expiry with the stock trading at $125, exercising the call to buy at $130 would be economically irrational (the client could buy shares in the market for $125). An out-of-the-money call expires worthless. The buyer's maximum loss is the premium paid. A call buyer has the right to buy; a call seller (writer) has the obligation to sell. Automatic conversion to shares occurs only for deep-in-the-money options under some brokerage exercise-by-exception rules, which does not apply here.

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