An unprofitable spread that occurs as a result of large commissions charged on the transaction, regardless of favorable market movements. An alligator spread is usually used in the options market to describe a collection of put and call options that may not be profitable.

Pricing models and a more efficient market can help reduce the traditional spread on a security, but it is commissions that create the alligator spread, not market inefficiencies. The commissions are dependent on a transaction's brokers. Investors should check the commission schedules carefully to avoid having their profits devoured by the alligator spread.