BMC UK is selling a 10.8% stake in BMC Minerals, triggering an $84 million block trade on the Australian Securities Exchange.
The transaction involves the sale of 29.5 million shares, with Barrenjoey Markets and Morgans Corporate acting as joint lead managers.
The deal was launched on Monday night, marking a significant early move in the secondary market for the junior miner.
BMC Minerals, which listed on the ASX in December, is a Canada-focused exploration company targeting silver and gold deposits.
The sale by BMC UK, a major shareholder, represents a substantial reduction in its ownership position.
For investors, the block trade introduces immediate supply pressure into a relatively thin float, potentially weighing on the share price in the short term.