The market cap numbers are part of a string of successes for Apple, including the iPhone 6's impressive launch earlier this year. More than 10 million iPhone 6 and iPhone 6 Plus devices were sold in their first three days of launch.
All of this is good news for Cook, who took over as Apple CEO in 2011, after Jobs stepped down. Many thought Jobs' shoes would be too big to fill and that Cook, an operations man, not an inventor like Jobs, would falter.