Nasdaq OMX has unveiled a new pricing and rebate scheme for its US markets, its second such change in two weeks, as the transatlantic exchange looks to claw back market share from low-cost rivals.

Nasdaq will increase the rebate it pays its biggest customers for posting orders onto its trading system to 29 cents per 100 shares, up from 28 cents currently. The discount, effective from March 31, affects brokers that handle more than 35 million shares per day on average.