Frasers Group said its stake in Hugo Boss topped 30% after latest acquisitions, with less than one week for its $2.2 billion offer to take full ownership of the German premium-apparel company to end. The U.K. retail group founded by British billionaire Mike Ashley said Tuesday that it acquired shares representing a 3.69% stake following the exercise of put options last week. This takes Frasers's holding in Hugo Boss to about 30.28%, excluding additional shares tendered into the takeover offer.

Frasers last month launched an offer to buy the stake in Hugo Boss it didn't already own for 1.93 billion euros ($2.20 billion). In response, Hugo Boss's managing supervisory boards unanimously recommended that shareholders reject the offer, saying the bid didn't adequately value its standalone prospects and seemed designed to enable Frasers to increase its shareholding beyond 30%.

The initial acceptance period for the offer is due to close on July 27, Frasers said.