The deal, valued at $225 million, is expected to be complete by the end of the year and follows Nike’s earlier announcement that is looking to sell off the firm, which specialises in the manufacture of football kits.
"It is difficult to divest any business, but this action will enable us to focus on our highest-potential growth opportunities," said Nike boss Mark Parker. "Umbro has a great heritage but, ultimately, as our category has evolved, we believe Nike football can serve the needs of footballers on and off the pitch."
Headquartered in New York, Iconix already owns a number of clothing brands, including Madonna’s Material Girl label and rapper Jay-Z’s Rocawear collection.
