Shares of Tesla Motors fell about 13 percent on Monday, the day the electric carmaker's lock-up period expired, flooding the stock market with shares.

The lock-up is a 180-day period in which sales of some of Tesla's shares after its initial public offering were restricted. Tesla debuted on the Nasdaq in late June.

As of September 30, Tesla had about 93.2 million common shares outstanding, the most of which was restricted under the lock-up agreement, according to a Tesla filing with U.S. regulators last month.

Beginning Monday, the owners of 75 million shares can sell their stock, Tesla said in the filing, which could depress the company's share price.

Tesla stock fell more than 13 percent at $26.14 on the Nasdaq. That was higher than its debut price of $17 per share. Tesla shares rose more than 40 percent on their first day of trading.

The company is readying its Model S, a luxury electric sedan, which it plans to launch in 2012.

But last week, Capstone Investments analyst Carter Driscoll initiated Tesla at a sell with a $22 target, saying the market for electric vehicles will not grow as quickly as expected.

Driscoll said he did not believe Tesla would be able to reach its projected earnings before interest and taxes target of 14 percent to 16 percent.

(Reporting by Deepa Seetharaman. Editing by Robert MacMillan)