Most of Wall Street's elite remember where they were and what they were doing every time the market has crashed. But what about what they were listening to?

According to Jared Dillian of Mauldin Economics, the top songs on the radio could be a useful predictor of where the market is going. 

"Music today is not quite as silly as it was in 1999 -- but it's almost there," Dillian said, hinting at a potential market top.

The top songs on the Billboard Hot 100 are a mixed bag -- there's Drake's "Nice For What," an upbeat hip-hop bopper labeled by many as the rapper's ode to feminism. But then in the second slot there's Childish Gambino's "This Is America," a blunt and cynical criticism of racial tension plaguing the U.S. at present.

The top songs on the Hot 100 list show that, for all of America's upbeat obsession with Zedd and Ariana Grande and Camila Cabello, we've still got a taste for the often fatalistic Post Malone and Migos and The Weeknd.

At least for now, playlists and radio hits don't appear to suggest the end of a nine-year-old bull market is nigh. But keep your ear to the airwaves, if past happenings are any indication a top could be forming. 

In March of 2000, the Nasdaq Composite I:IXIC peaked at 5,048.62 in the prelude to what would become a massive dot-com bubble burst. That week, before things took a drastic turn for the worse, the top song on the Billboard Hot 100 was "Amazed" by Lonestar.

In the second slot was "I Knew I Loved You" by Savage Garden.

Populating the top 20 most popular songs that week in March 2000 were the likes of 'N Sync, Celine Dion, the Backstreet Boys, Christina Aguilera, Britney Spears and Destiny's Child. In other words, people were listening to a whole lot of bubblegum pop that captured the optimism of the moment.

Dillian points out that the uber-happy pop hits that dominated airwaves around Y2K served as a stark contrast to the radio's much darker music around 1994. The country was coming out of a recession and people preferred the somber, and often ominous, music from bands like Nirvana and Nine Inch Nails.

"You will know we are in a bear market if metal, industrial or some of the harder genres of hip-hop return to the scene," Dillian said. "But that will be a severely lagging indicator, not a leading indicator. The leading indicator is that we have so much bubblegum pop around."

Nine Inch Nails made metal mainstream, Dillian said. The band's album "The Downward Spiral" went platinum four times -- people of all walks of life wanted to listen to dark music that included nihilistic and destructive lyrics like "I am the bullet in the gun (and I control you), I am the truth from which you run (and I control you), I am the silencing machine (and I control you), I am the end of all your dreams (and I control you)."

"If Nine Inch Nails formed today, they'd be playing Elks Lodges in Eastern Ohio, not clogging up MTV with music videos," Dillian wrote.

People were in a bad mood in the early nineties because unemployment had been high, money had been lost and the market was stuck in a rut. Within the decade, mainstream America went from Nirvana to Britney Spears. During that same time, we came out of a recession and into a bull market.

In the early months of 2009 just before the Dow Jones Industrial Average I:DJI and S&P 500 I:GSPC bottomed in March, the top Billboard Hot 100 songs were from artists including Lady Gaga, Flo-Rida, Beyonce and the Black Eyed Peas. Lot's of happy dance hits were blaring through the speakers just before the economy skidded to its lows in the Great Recession.

Best charge up that Apple (AAPL) - Get Report iPhone and keep the music going.