Stephen Schwarzman, Blackstone CEO, said taking Walgreens Boots Alliance private would be a “stretch” right now as investors have become more discriminating, Bloomberg reported. “You need at least $20 billion of equity. Could you find that in today’s world? Maybe,” the story said, which quoted Schwarzman’s comments during a Reuters Newsmakers event. The Blackstone co-founder said mega-deals are “straining the system,” according to the story.