Facebook is making a mysterious announcement at its California headquarters at 1 p.m. ET today. Will it be about mobile, a video chat app, a better search feature, a change to its timeline, or even a Facebook phone?  

We don't know, but we do know Wall Street has been bidding the stock higher in anticipation.  Facebook (FB) shares are up 16% since the end of last year, including the 2.5% decline Monday.

Analysts are upbeat for FB momentum this year. Cantor Fitzgerald just made Facebook one of its "highest conviction calls" for 2013, while JPMorgan Chase elevated FB shares to a "top large-cap pick" for the Internet sector.

The North American International Auto Show is underway in Detroit, home of America's largest automakers. But Japanese and German automakers are stealing their market share.

Japan's Toyota once again becomes the largest automaker in the world, selling 9.7 million vehicles last year versus General Motors' (GM) 9.29 million. Toyota came roaring back after 2011's earthquake and tsunami in Japan with a 22% global sales gain. Not only did production return to normal, but Toyota also rolled out new versions of popular models like the Camry.  

Toyota is expected to retain its title as world's top automaker this year, too. But GM could easily be pushed from No. 2 down to No. 3, as Volkswagen models increase in popularity.

Meanwhile, on Wall Street, futures are pointing to a lower open. Markets ended mixed Monday, with the Dow up 19 points and higher for the fourth straight session.  

Apple (AAPL) was a drag on the broader Nasdaq and S&P 500; the technology giant's stock sank 3.6% following a report that demand for the iPhone 5 may be weaker than expected.

Lauren Simonetti joined FOX Business Network (FBN) in September 2007 as a field producer and became a reporter for the network in September 2011.