Is Coca-Cola (NYSE:KO) or PepsiCo (NYSE:PEP) king on the Billboard Top 20? The answer may surprise you. PepsiCo, which ranked 50th among consumer brands mentioned in Top 20 songs in 2004, beat Coke, which rated 75th.

A company you've probably never heard of, Agenda Inc., monitors the mentioning of brands in popular music and has a clever name for its service: American Brandstand. More specifically, the company has "tracked all the mentions of brands in the lyrics of the Billboard Top 20 singles chart."

Here are some interesting findings: Overall, branding is high, with about 40% of Top 20 songs mentioning at least one brand in both 2004 and 2003. It's mostly hip-hop songs that are doing the plugging. In fact, only one non-hip-hop song in the Top 20, Jessica Simpson's "With You," mentioned a brand -- Levi Strauss. New brands on the list include LVMH Moet Hennessy Louis Vuitton's (NASDAQ:LVMHY) Dom Perignon (tied for 16th place in 2004), Viacom's (NYSE:VIA) MTV (also 16th), and The Limited's (NYSE:LTD) Victoria's Secret (19th).

The top brand in 2004 was General Motors' (NYSE:GM) Cadillac, followed by Hennessy, DaimlerChrysler's (NYSE:DCX) Mercedes, Rolls Royce, Gucci, Ford's (NYSE:F) Jaguar, Cristal, GM's Chevrolet, Bentley, and Maybach (DaimlerChrysler's high-end brand, which is featured in TV's "The Apprentice"). Cadillac ranked fourth last year with 46 mentions and jumped to the top spot this year with 73 mentions. Apparently, it's as cool a brand as can be right now. Or at least it was in 2004.

How might an investor view this kind of information? Well, a cynical one might suspect that these musicians are angling for some payouts by mentioning brands. If a song is picked up by a company and used in advertising and marketing, the singer/songwriter stands to make some extra money, often a lot of it.

If a company you're invested in, or looking to buy, sports some prestigious brands, it could pay to follow how much it's sung about. Fewer song mentions might signal that the brand is losing favor, which is likely to lead to falling profits and a sagging stock price.

You've now got a financial reason to turn on your radio and tune in -- call it investment research.

And if you'd rather not listen to hip-hop music, consider discovering some hot brands via stocks recommended in our investing newsletters. You can try one or more of them for free. Check out their impressive performance to see why you might want to try them.

Coca-Cola is a Motley Fool Inside Value pick.

Longtime Fool contributor Selena Maranjian owns shares of PepsiCo and Coca-Cola.