LEADING THE DAY: Tech companies led the way Wednesday as stocks climbed to their highest levels since 2008, The Washington Post reported.

Strong reports from tech stalwarts such as Intel, IBM and Apple could be good indicators for the rest of the economy, signaling that other companies are in the position to make investments in equipment and technology.

Apple earnings: In an earnings call yesterday, Apple reported $24.67 billion in earnings, up 83 percent over last year. Record-breaking sales for the iPhone made up for lower-than-expected sales of the iPad. Apple COO Tim Cook, who is the company’s acting CEO in Steve Jobs’s absence, said iPad sales were low because of supply problems.

Looking ahead, Cook said that the disaster in Japan would not affect Apple’s supply chain, though he did forecast its effect on the Japanese economy would lower Apple’s revenue by about 1 percent. He did not comment on speculation that the iPhone 5 will launch in the fall instead of the summer.

iPhone tracking:Several members of Congress have called on Apple to explain a tracking file in its 3G devices. The file was found by two researchers who were looking for a way to visualize mobile data.

Sen. Al Franken (D-Minn.) has written a letter to Apple asking for more information on why the company is collecting the information. Rep. Jay Inslee (D-Wash.) issued a statement saying he is “deeply disturbed” by the report, The Hill reported.

An FCC official told Politico that the the agency is looking into the matter.

Nokia, Microsoft sign agreement: Finalizing their agreement from last month, Nokia and Microsoft have officially signed a definitive contract to put the Windows mobile platform on all Nokia phones. The agreement was signed ahead of schedule.

In an interview with All Things Digital’s Ina Fried, Microsoft phone head Andy Lees said, “We’ve gotten to where we have gotten to faster than we thought. Now we know who is exactly writing each piece of code.”

Amazon tablet: Amazon has long been rumored to be working on a tablet, and a report from the tech blog GDGT speculates that Samsung is already working on the project. In the report, Engadget founder Peter Rojas makes a well-reasoned argument that the company could be the only one who can take on Apple’s iPad, working off of its existing customer base.