Rumor has it that Amazon will be opening 400 new bookstores—but is it actually going to happen? 

"I would never doubt Amazon doing anything that seems unlikely or retroactive," tech writer Joan Solsman tells CNBC. "I mean, drone deliveries? No one would have thought of that."

After three quarters of profits in a row, Amazon could be looking into the brick-and-mortar expansion as a way to strengthen investor confidence and challenge main rival Barnes & Noble head-on.

Of course, between finding locations and hiring employees, it would take years for Amazon to roll out a significant brick-and-mortar presence, Solsman says.

The e-commerce giant, which opened its first physical store in Seattle last fall, has kept mum on the expansion until General Growth Properties CEO Sandeep Mathrani dropped the bomb on Tuesday.

UPDATE: Since the bombshell revelation, General Growth Properties released a statement distancing itself from Mathrani's original comments, saying they were "not intended" to represent Amazon's plans.