Billionaire Elon Musk claims to have made $300,000 in hat sales for his tunneling venture called The Boring Co.
Musk founded the tunneling firm after becoming frustrated with traffic in Los Angeles. His idea is to build a series of tunnels under LA with cars ferried around on pods at around 125 mph.
The cap finally went on sale in October for $20 each.
Now Musk has revealed that proceeds from hat sales are more than $300,000 and the money will be used to fund "more boring." That would mean around 15,000 caps have been sold.
Musk has been slowly revealing parts of the project on social media. In July, he showed off the elevator that would lower cars to the underground network of tunnels in order to shoot them across the city. He then said that his second digging machine was almost ready for action, before sharing the first picture of a tunnel dug in LA.
In August, Musk received approval from the City Council in Hawthorne, California, to build a two-mile test tunnel.
Musk jokingly referred to the fundraising via hat sales as an "initial hat offering," taking a dig at the initial coin offering seen in the cryptocurrency world. An ICO is when a company sells digital tokens in exchange for cryptocurrency, but investors don't get a stake in the firm. ICOs so far have got a bad rap, with one start-up called Confido raising $375,000 then disappearing with the money.