Apple is world's first publicly traded company worth $1tn

A 3 percent climb in share price made Apple the world's first trillion-dollar publicly-traded company.

Apple's ascent from the brink of bankruptcy to the world's most valuable public company has been a business tour de force, marked by rapid innovation, a series of smash-hit products and the creation of a sophisticated, globe-spanning supply chain that keeps costs down while producing enormous volumes of cutting-edge devices.

That ascent has also been marked by controversy, tragedy and challenges. Apple's aggressive use of outside manufacturers in China, for example, has led to criticism that it is taking advantage of poorly paid workers in other countries and robbing Americans of good manufacturing jobs. The company faces numerous questions about how it can continue to grow.

Gas giant Saudi Aramco has twice Apple's revenues and is valued at up to $2tn. But you can't buy yourself a chunk of it-not yet, anyway.