Covanta Holding Corp. CVA, +7.48%, the world's biggest operator of waste-to-energy facilities, said Wednesday it has agreed to be acquired by EQT Infrastructure for $20.25 a share in cash in a deal valued at $5.3 billion. The price is equal to a 37% premium over Covanta's unaffected share price of $14.78 on June 8, the day before deal speculation sent it higher. The deal is expected to close by year-end. EQT will work with Covanta's existing management to grow the company, which has a portfolio of assets in North America, Europe and the U.K. Covanta's more than 40 facilities process about 21 million tons of waste a year from municipalities and businesses and convert it into renewable energy that powers more than a million homes. Covanta shares rose 7% premarket on the news and are up 41.5% in the year to date, while the S&P 500 SPX, +0.35% has gained 16%.