The pitched battle for office REIT Equity Office Properties Trust (NYSE: EOP) is either winding down or about to get even more heated. The Chicago-based landlord founded by Sam Zell has given a Vornado-led investor group until midnight to counter Blackstone’s sweetened $38.3 billion offer for the company.

Still, the door remains open until Monday’s shareholder meeting in Chicago since the board and shareholders of EOP will have the ultimate say on the deal. Late today, however, media reports stated that sources close to the deal predict that Vornado will indeed make a counter offer later today.

The saga leading up to this critical point began nearly two weeks ago when the Vornado group made a $21.4 billion cash/stock offer on the company, or $52 per share, countering Blackstone’s initial bid of $48.50 per share.

If Blackstone’s most recent offer of $54 per share wins the day, the private equity giant will be buying EOP at a 20.8% premium to the closing share price – about $45 per share -- prior to the initial announcement of the deal on November 19th.

However, Blackstone may be paying two premiums. Yesterday, stock valuation and advisory firm ValuEngine Inc. released a research report, stating that EOP shares are 9.19% overvalued, and that the stock should be trading at $50.24. The firm also forecast the stock price to rise to $59.67 in the next 12 months. EOP stock closed at $54.66 yesterday.

Earlier this week, independent proxy advisory firm Institutional Shareholder Services (ISS) urged EOP shareholders to give Blackstone’s all-cash bid their blessing. It won’t be known how EOP feels about the offer for a few days: shareholders won’t formally vote on the Blackstone proposal until Monday. Another reason why EOP may accept Blackstone’s bid – EOP stands to pay a $500 million break-up fee if the deal doesn’t go through.

We’d like to hear your thoughts on this developing story. Email parke.chapman@penton.com.

Below is a recent sampling of what NREI readers had to say about the unfolding EOP deal:

“Blackstone will prevail. They have too much money to spend and don’t have to fear bad press if they overpay.” --Nathan Isikoff

“Who will win in the end will be determined by Sam Zell. If [Zell is] worried about his tax position, he’ll go with Vornado’s 60% cash -- 40% OP [operating partnership] unit offer. If he really wants to pull chips off the table, he’ll take Blackstone’s all-cash offer.” --David Sislen