Best Bid

Worked example

In a binary market, the YES contract is offered at 42¢ and the NO contract at 56¢. The best bid for YES is 41¢ and for NO is 55¢. If you place market orders to buy both YES and NO, you’d pay 98¢ total, locking in a 2¢ edge if you can execute both legs.

FAQ

What is the difference between best bid and best ask?

Best bid is the highest price someone is willing to pay to buy, while best ask is the lowest price someone is willing to accept to sell. The inside spread is best ask minus best bid.

Why does best bid matter for arbitrage?

A higher best bid improves your chance to buy at favorable prices and, when paired with a favorable best ask, helps identify edge opportunities in intra-market arbitrage.

How is the best bid displayed in Kalshi data?

Best bid appears in the order book snapshot and WS deltas, updating as new bids come in or existing bids change.

Related terms

• Yes Contract
  A YES contract is the binary Kalshi market side that pays $1 if the event resolves true, $0 otherwise.
• No Contract
  The NO contract is the opposite side of a binary Kalshi market, paying $1 if the event does not occur.
• Best Ask
  The lowest price sellers are willing to accept for a contract side (YES/NO) on the current Kalshi order book.
• Tick Size
  Tick size is the minimum price increment by which Kalshi contract prices can move (1 cent).
• Event Ticker
  A code that groups mutually exclusive Kalshi markets under one event (e.g., CPIYY-26MAR) and links its child YES/NO contracts.