And with Apple holding $194 billion in cash, Pandora's sub-$4 billion stock market value would seem to carry little resistance to the iPhone maker's never-ending ability to spend on marketing and product development.
But here's the thing. In Pandora's decade on the market, the company has grown through every previous Apple threat, even the ones that were supposed to sink it.
Most notably, in September 2013, Apple rolled out iTunes Radio, an ad-based challenger to Pandora. When rumors of a pending announcement were reported in early June, Pandora's stock sank 15 percent in two days.
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Yet after a brief dip in listeners, Pandora (and the stock) recouped its losses. To this day, monthly active users and engagement continue to increase, with 79.2 million people now listening for 22.3 hours per month.
By Pandora's estimate, the service reached 10 percent of all U.S. radio listening in March for the first time ever. Creating a personalized experience that satisfies music lovers and keeps them coming back has proven to be challenging for newer entrants, big and small.
"It's a fantastically hard thing to do," said Pandora founder Tim Westergren, in an interview on Monday. "New products generate a lot of trials, but the real test is sustained listening."
At Apple's Worldwide Developers Conference on Monday, the company said its new service would blend radio, a hand-picked music experience from experts and a social network of sorts to help artists communicate with fans.