Noble Helium (ASX:NHE) signed a convertible securities and placement deal with Obsidian Global to raise up to $2.5 million through the issue of convertible notes, according to a Tuesday filing with the Australian bourse.

The initial tranche will raise $850,000, with additional tranches of up to $1.65 million within 12 months, subject to conditions, the filing said.

The interest-free notes have a face value of AU$1.15, mature in 36 months, and are convertible at Obsidian's option at AU$0.10 or a variable price after February 2025, with a floor of AU$0.03.

Noble Helium also has the option to repay the notes in cash at a 5% premium with five days' notice, the filing added.

The Tranche 1 notes and placement shares are subject to an aggregate issue and conversion limit of 62.3 million shares, based on the current exchange rate and the conversion floor price of AU$0.03.

They will be issued under the company's placement capacity under the ASX listing rule 7.1, the filing said.

Shares of the company slid 2% at market close.