Staples and Office Depot on Wednesday said their boards voted to extend a deadline to approve a merger pact that has so far been thwarted by U.S. antitrust regulators. Investors shouldn't hold their breath for a deal to go through — all the three-month postponement amounts to is a bunch of wishful thinking.

Sure, extending the deadline will give the office supply chains time to fight the Federal Trade Commission's lawsuit to block the transaction and go through a trial set to begin March 21. But it's a matter of going through the motions, so to speak, for management — many of whom stand to come out on the losing end of any tie-up.

Shares of Staples and Office Depot fell by as much as 6 percent and 4 percent, respectively, on Wednesday. Since the merger agreement was announced last February, both companies' stock prices have dropped by roughly 50 percent.