ioneer (ASX:INR) secured around $50 million from institutional, professional, and sophisticated investors through a single-tranche placement of around 400 million new shares at AU$0.18 each, representing a 14.3% discount to its closing price on Wednesday, according to a Friday filing with the Australian bourse.

The company will issue new shares under its existing placement capacity, which will rank equally with the existing ordinary shares, the filing said.

The funds will be used to accelerate the company's wholly-owned Rhyolite Ridge lithium-boron project, covering early works, project readiness, environmental permitting, other project costs, and supporting working capital, the filing added.

The company's shares tumbled around 24% at market close on Friday.