OpenDoor Trading LLC, a U.S. bond trading platform, has raised$10 million.

The company will use the funds to develop a trading platformfor off-the-run Treasuries and Treasury Inflation Protected Securities, or TIPS.The platform is due to be launched in the fall.

An unnamed female investor and John Brynjolfsson have investedin the company in the latest investment round. Hartfield Titus & Donnelly LLC, a municipal broker-dealer,also owns a stake in OpenDoor.

OpenDoor Co-Founder and CEO Susan Estes and the other femaleinvestor now control more than 65% of the voting interest in the company. The capitalraise was completed at a pre-money valuation of $40 million.

Estes and Brian Meehan co-founded OpenDoor less than three yearsago, which claims to improve liquidity across off-the-run Treasuries and TIPS, througha proprietary trading platform. The company's initial seed funding round took placein late 2015.