An option trading strategy that is executed by selling a number of out of the money call options exceeding the number of long call options. The short and long call options make up a ratio spread that results in a larger profit when the underlying closes within the range bounded by the strike prices of the long and short options. This ratio spread eliminates upfront payment, and therefore reduces the risk of establishing this position.

The ratio bull spread is also known as a bull ratio spread, a call ratio spread, and a ratio call spread.