Blackstone's Jonathan Gray said the firm's recent investments in warehousing should prove valuable as more and more consumers go online to shop. 

Gray, who became the firm's president and chief operating officer earlier this year, explained that Blackstone has purchased more than 550 million square feet of warehousing since 2010. 

"As you think about investing, you're trying to think about sort of where the puck's going to, what's happening.  We came to a simple view that online sales were going to grow," he said at the Delivering Alpha Conference in New York last week. " Now I don't think even we had an anticipation of what it would be, but they've been growing at 15, 20 percent a year now for almost a decade and if anything are accelerating as Amazon's gone from two days to two hours."