Ford (NYSE:F) had a great April.

The car manufacturer announced that sales in April rose 18% when pitted against April of last year. Car sales were up 21%, along with a 16% increase in trucks and utilities. 

This is great news for Sirius XM Radio (NASDAQ:SIRI). New car sales are the lifeblood of subscriber growth. Satellite radio receivers are now factory installations in more than two thirds of all new cars, and buyers of new vehicles are converting to premium subscribers at a 44% clip after participating in the free trial plans. 

Sirius XM already announced healthy subscriber growth during the first three months of the year, closing out the month of March with 24.4 million subscribers. Strong car sales in April at Ford and other auto makers bode well for Sirius XM's future.

In this video, longtime Fool contributor Rick Munarriz explains why this matters, even at a time when Sirius XM keeps pointing to the used car market and connected cars as its incremental opportunities for growth.

Longtime Fool contributor Rick Munarriz owns shares of Ford. The Motley Fool recommends Ford. The Motley Fool owns shares of Ford. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.