Every time a cellphone rings, a Senator makes a larger return on his investment!

In 2010, Sen. Mark Warner was able to boast that he was the sixth-richest Member of Congress, with an estimated net worth of at least $70 million (his latest financial disclosure forms will be filed soon, so we’ll know whether he still has the cash).

The Virginia Democrat made the bulk of his money by persuading a group of investors to buy cellular telephone licenses in the 1980s and then later as an early investor in Nextel (now Sprint).

So when an audience member’s cellphone rang during his speech at the Atlantic’s New Work Era Summit on Tuesday morning, Warner didn’t even sweat it, making a joke that he has made before.

“As founder of Nextel, when you all hear an annoying sound, I hear cha-ching, cha-ching,” he said.

Then, just to add a rim shot to his joke, 30 seconds later, Warner’s own phone went off.