Options mechanics
What is the Option Chain and how do I read bid, ask, volume, and open interest lines?
By Easy Money Scanner · Educational reference · Not investment advice
The short answer
The option chain is the listing of all available strikes and expirations for an underlying, displaying bid, ask, last price, volume, open interest, and implied volatility for each contract.
How it works
Bid is the highest price buyers offer, ask is the lowest price sellers accept, volume shows contracts traded that day, and open interest shows total outstanding contracts not yet closed.
An example
On an XYZ chain, a 50 call showing bid 2.10, ask 2.20, volume 500, and open interest 3,000 indicates active trading with a ten-cent spread between buyers and sellers.
Risk & limitations
Wide bid-ask spreads on an option chain often signal low liquidity, which can increase slippage costs when entering or exiting positions at market prices.
Examples are hypothetical, not trade recommendations. US contract and regulatory references do not automatically apply in Canada. Rules, margin requirements and broker policies can change; confirm them with the relevant authority and your broker.