Privately held X.com plans to find a candidate within the next two months, said Musk, the company's largest stakeholder. He added that he initiated the search two weeks ago.
X.com, which merged with PayPal in March, will soon have 4 million registered users. Musk said X.com is looking for a "superstar CEO," one with more experience than Musk at directing a growing financial institution. PayPal allows consumers and businesses to transfer money via email.
"One has to recognize where one's strengths lie," Musk said. "It's more interesting for me in the early stages of running a company, where the concentration is all on developing the product...I'm not really interested in administration."
Musk is leaving at a time when X.com is seeing enormous growth but has also felt growing pains. Some customers have complained recently about X.com's policy of charging anyone using the PayPal service for business purposes.
This is the second time that the 29-year-old Musk has stepped down as CEO in favor of a more experienced leader. X.com tapped former Intuit chief Bill Harris last December to run the company. Musk returned when Harris resigned after only five months.
Musk's departure is the latest example of a young Net entrepreneur, adept at creating Web businesses but lacking in administrative know-how, making way for a more seasoned leader. Joseph Park, founder of Web convenience store Kozmo.com; Todd Krizelman and Stephan Paternot of media content site Globe.com; and Danny Robinson at infrastructure company Spinway.com are just a few.
Before launching X.com last March, Musk founded directory company Zip2 in 1995. He sold it in 1999 to AltaVista for $305 million--at that time the largest all-cash transaction for an Internet company, Musk said.
Musk plans to take a couple of months off once a new CEO is found and then start a new company. In the meantime, he will serve as interim CEO until his replacement is found.
"I guess you can say that I'm a serial entrepreneur."