Caesars Entertainment’s largest unit is preparing to file for bankruptcy protection immediately in the final gambit of a year-long attempt to salvage a soured buyout.

Caesars’ Chapter 11 filing would launch the final stage of Apollo Global Management’s effort to save some of its $1.7bn investment in the company, which it took private in 2008 with fellow buyout firm TPG.

A Chapter 11 petition would follow months of contentious negotiations with creditors. The unit’s collection of casinos and hotels, including much of the Las Vegas Strip’s iconic Caesars Palace, is expected to operate normally as it works to persuade a judge to approve a restructuring plan that would transform it into a real-estate investment trust.