There's an old saying in deal-making: "Buying a company is easy. The hard part is making it work once you own it."

That's the situation for Blackstone's star real estate guru, Jonathan Gray. He won the bidding for Equity Office Properties (NYSE: EOP), which cost about $39 billion.

For a deal like this, there is often a big party.But that's not what Gray did. Apparently, he is constantly scared that the deal will fail. After all, the last similar mega deal was the buyout of RJR Nabisco (back in 1989), which almost imploded.

Interestingly enough, while Gray was bidding for EOP, he was also planning and even negotiating the exit strategy. In fact, he is already unloading properties so as to pay down the enormous debt.

Moreover, he's a big-time Chicago Bears fan and despite having tickets to the Super Bowl, he instead opted to spend his time wheeling and dealing to get the EOP deal done.

Tom Taulli is the author of various books, including the Complete M&A Handbook and the EDGAR-Online Guide to Decoding Financial Statements.

It's a good week for Sam Zell, who sold Equity Office Properties Trust (NYSE: EOP) for $39 billion. In all, he takes about $900 million. At age 65, he is certainly a veteran player of the real estate game.

One of his peers, Steven Roth – who is the CEO of Vornado Realty Trust (NYSE: VNO) – is 64 years old. He dropped out of the bidding for EOP because he thought the valuation was too rich.

And, today, another Old Guard real estate mogul, Mortimer Zuckerman, is taking money off the table. He is the chairman of Boston Properties Inc. (NYSE: BXP) and is 68 years old.

According to an SEC filing, he is selling roughly $75 million of his stock.

But, despite all of this, Blackstone's real estate chief, Jonathan Gray, was willing to buy EOP – which is likely to have a big impact on real estate valuations.

His age: 37.

Tom Taulli is the author of various books, including the Complete M&A Handbook and the EDGAR-Online Guide to Decoding Financial Statements.