Twitter Inc., the microblogging service with more than 100 million users, received a $300 million investment from Saudi Prince Alwaleed bin Talal as it pushes through a redesign of its site to attract advertisers.

Alwaleed, who leads the 2011 Arab Rich List, and his investment company agreed to buy a “strategic stake” in Twitter, Kingdom Holding said today. A strategic holding means more than 3 percent, Ahmed Halawani, a Kingdom Holding director, said in an interview. That would give the San Francisco-based company a valuation exceeding $10 billion.

The investment by Alwaleed, the largest individual investor in Citigroup Inc. (C) and owner of a stake in News Corp. (NWSA), may give Twitter more time to pursue growth before selling shares an initial public offering, a path that’s likely to be pursued by rival Facebook Inc. Twitter, which lets its users send 140- character messages, is revamping the site to make it faster and simpler to navigate.

“They are looking to give themselves some more running space,” said Jeff Mann, an analyst at Gartner in Amsterdam. “Their strategy has always been first get big. They’re still holding reasonably close to that. Having a big audience is more important than a short-term revenue stream.”