CHICAGO — Oaktree Capital Management, the Los Angeles-based investment firm that was once Tronc's largest shareholder, sold its remaining 3.74 million shares back to the publishing company Thursday in a deal valued at more than $56 million.

The buyback, priced at $15 per share, reduces the number of outstanding shares in Tronc, owner of the Chicago Tribune, Los Angeles Times and other major newspapers, from 36.44 million to 32.7 million. As a result, the deal increases the stakes of its remaining shareholders, including Chairman Michael Ferro.