The deal included $1.6 billion in debt assumption and $30 per share in cash. According to a December release about the transaction, the price is an 18% premium over the previous week's closing stock price and a 26% premium over the company's average stock price since Realogy separated from Cendant Corp. on Aug. 1. Realogy is considered to be one of the largest real estate franchisors in the world and includes such brands as Century 21, Coldwell Banker, Coldwell Banker Commercial, Sotheby's International Realty, NRT Inc., Cartus and Title Resource Group..

The merger was first made public in December, at which time Realogy's CEO and chairman Henry Silverman said, "After careful consideration, our board of directors has concluded that this transaction is in the best interests of Realogy and out stockholders. It will enable stockholders to realize the value of Realogy's fundamentally strong businesses. At the same time, the valuation takes into account the substantial pressures and uncertainties facing the residential real estate markets that may well continue for some time."

The deal then received shareholder approval at the end of March.

The Realogy merger is just one in a slew of major transactions Apollo has undergone in the last five months. In March, Claire's Stores agreed to be purchased by Apollo for $3.1 billion, as GSR reported.

In late February Apollo offered to purchase Countrywide plc, a British residential real estate service provider, for one billion pounds ($2 billion).

In December, Apollo agreed to purchase Harrah's Entertainment for $27.8 billion in conjunction with Texas Pacific Group.

At the beginning of April, Apollo was said to be mulling over a $1.5-billion private offering. News that came to light just a week after the Blackstone Group made public its plans to conduct a $4-billion initial public offering.