Elon Musk has simple advice for Twitter's new CEO about running two companies: Don't do it

By Jillian D'onfro

Jack Dorsey joined the elite (and very small) club of CEOs who run two companies this week, now that he is the boss at both Twitter and digital payments start-up Square.
But the advice from one of the other prominent members of the dual-CEO club is not very inspiring: don't do it.

During an appearance at Vanity Fair's New Establishment Summit on Tuesday, Elon Musk was asked about his thoughts on doing double-duty at two companies in light of the Jack Dorsey news.

"I wouldn't recommend running two companies - it really deceases your freedom quite a lot," Musk replied.

Musk knows a thing about running two companies. The South African-born entrepreneur is the CEO of electric car maker Tesla Motors and the CEO of space exploration company SpaceX.

Musk said that he spends about 70% of his day focused on engineering and design.

He estimated that he spends roughly 2% to 3% of his time doing press stuff, such as his on-stage appearance at the Vanity Fair summit. And apparently even that is too much. "I'm going to reduce it even further to only about 1% of my time," said Musk.