The Boston Options Exchange is changing its pricing model to attract more market makers and liquidity as the US market undergoes structural and regulatory changes that are expected to boost volumes by 40% next year.

Since January, US options markets have been able to quote in pennies rather than in nickels and dimes for 13 blue-chip stock options in a pilot scheme. The pilot, whose initial phase expired on July 26, has now been extended until the end of September.