Warrant - An options contract often sold with another security. For instance, corporate bonds may be sold with warrants to buy common stock of that corporation. Warrants are generally detachable.

Weak form efficiency - A form of pricing efficiency where the price of the security reflects the past price and trading history of the security. Related: Semistrong form efficiency, Strong form efficiency

Weighted-average portfolio yield - The weighted average of the yield of all the bonds in a portfolio.

Wild card option - The right of the seller of a Treasury bond futures contract to give notice of intent to deliver at or before 8:00 p.m. Chicago time after the closing of the exchange (3:15 p.m. Chicago time) when the futures settlement price has been fixed. Related: Timing option

Window contract - A guaranteed investment contract purchased with deposits over some future designated time period (the "window"), usually between 3 and 12 months. All deposits made are guaranteed the same credit rating. Related: Bullet contract

Wire house - A firm operating a private wire to its own branch offices or to other firms, commission houses or brokerage houses.

Writer - The seller of an option.