A-Mark Precious Metals (AMRK) said Monday it will acquire Spectrum Group International for $92 million, gaining control of Stack's Bowers Galleries, a major rare coin and currency auction house, and Spectrum Wine, a global fine wine auctioneer, retailer, and storage provider.

The company said the deal, comprised of 50% in cash and 50% in stock, will expand its reach into adjacent luxury markets, offering the potential for higher margins and a broader customer base.

The acquisition is expected to close within 30 days, it added.

Shares were over 4% lower in recent premarket activity.