Sadly, Gene Simmons and Paul Stanley do not show up in full Kiss makeup at LA Kiss games, scribbling scouting notes on Mac and Jack linebackers and fullback delays. "No, that probably will not happen," says Doc McGhee, the band's longtime manager, who co-owns the Arena Football League team with the stars behind "Rock And Roll All Nite" and "Detroit Rock Ciy."

Still, Simmons and Stanley are hands-on owners, weighing in on offensive coordinators and quarterback signings while focusing on marketing and promotion.

"My artists don't try to run things that they can't handle — ­they understand their path and they understand their lane," says McGhee, who has also managed artists such as Bon Jovi, Mötley Crüe and Darius Rucker. "So it's easy for them to get in and out of deals. I've watched artists go in and do clothing deals and lose fortunes, and I've watched them go into deals and make fortunes. It's basically because one's savvy and one's not."

Rock stars have been investing in side businesses for decades — the Who's Keith Moon famously ran his Oxfordshire, England, hotel the Crown and Cushion into the ground; Booker T And The M.G.'s guitarist Steve Cropper ran a Nashville, Tenn., travel agency for years; Michael Jackson's financial lifeline was his multimillion-dollar investment in the Beatles' music publishing catalog.

More recently, Jay Z expanded his hip-hop empire into a business one, investing in the NBA's Brooklyn Nets, opening a sports agency and, for $56 million, buying the Tidal streaming service. Artists such as Bono, Justin Timberlake, Linkin Park, and Bruno Mars have also diversified into online startups and venture capital, placing bets on new companies with the hopes of becoming the next Warren Buffett rather than simply the next Elvis.

Some artists have had mixed success in the world of private equity and personal investments: Timberlake has built a presence in Silicon Valley, joining an investor group to throw in $35 million for the revamped MySpace, then put cash into audio specialist AfterMaster; Linkin Park launched Machine Shop Ventures in 2015 and have invested in companies such as Lyft, Robinhood and Shyp, which specialize in ride-sharing, stock trading and shipping, respectively. Hip-hop artist Nas and his firm QueensBridge Venture Partners have invested in more than 40 startups, ranging from bitcoin company BitFury to file hosting service Dropbox.

The stars jump in for different reasons. For some, it's the money. Others want to prove themselves in a business not related to their core product of releasing albums and performing concerts.

"To be around that kind of culture with people who are super cutting-edge thinkers who are so smart, that's inspiring to me," said Linkin Park frontman Mike Shinoda in an interview with CNNMoney.

For others, it's to make a difference. Bono's agenda is to draw funds and attention to his cause: fighting world hunger.

But some just want to have fun. Over the years, Duran Duran's Simon Le Bon has sunk cash into what he calls a "cross-platform media project in the '90s" (which went bust), classic cars, motorcycles, and wine (the latter of which he says has increased 700 percent in value).

"The big lesson I've learned is never do anything for money," says Le Bon, who with his wife Yasmin and business partner Nick Wood runs Syn Entertainment, a British company that creates original music for companies and media. "You should do something because your heart's in it."

One of the music industry's most prominent investors is artist manager Troy Carter, who helped turn Lady Gaga into a megastar and currently represents Meghan Trainor and Kamasi Washington, among others. He started investing about five years ago, meeting with venture capitalist Paul Graham, who co-founded the firm Y Combinator, before setting up a team of his own. Carter says it took a couple years for Silicon Valley tech and business leaders to consider his group "serious investors." They kept asking, "Can you guys get us a celebrity for our product?"

But Carter developed a reputation for savvy investments, funneling venture capital on hit companies such as Uber, Lyft, Dropbox, Spotify, and Warby Parker. Eventually, he expanded to his own startup-incubator, tearing out a gym at his longtime talent agency, Atom Factory, to create Smashd Labs and give its inhabitants more space to stretch out. Some 200 applicants applied to set up at Smashd and Carter picked six, including WeTransfer and concert merchandise line-skipping company Sidestep.

"I'm a geek — I'm reading business school case studies over the weekend," Carter says. "I just love to be there early. It's less exciting to me if I'm investing in Uber Series G or going out and signing an artist who's been established [for] the last 20 to 30 years."

For investment-minded artists, risk is a crucial factor on deciding whether to get involved in high-level companies. Many artists, focused on making music and the rigors of touring, leave their finances to trustworthy managers and attorneys. And many who dabble in finance don't have the patience for venture capital.

David Kalt, CEO of online music-gear marketplace Reverb.com, recruited Cheap Trick guitarist Rick Nielsen and country star Brad Paisley as early investors. Both spread the word about the site through interviews and social media. Two years after launching in 2013, the company has sold more than $120 million worth of products, recently earning a $25 million round of funding from Summit Partners.

Early on, Kalt reached out to several well-known artists for venture investments. "Their managers got nervous. Investing in venture capital was very foreign to them. It's not for everyone," he says. "It's like, 'Well, what do I get out of it this year?' 'Well, nothing this year — it's like a five- or 10-year thing.' And you could have some frustration."

The uncertainty is enough to make even veteran artists stick to plans — and people — they know. Aerosmith drummer Joey Kramer lent his name to Rockin' & Roastin', an organic coffee brand in 2012, only after partnering with former Hewlett Packard and Compaq executive Roy Mann (who happens to be his brother-in-law) and Frank Cimler (his attorney).

"You've got to be very careful who you get involved with — especially someone like myself, because everyone just sees dollar signs," Kramer says. "We have our days, our arguments, but bottom line, we get along and trust each other."

Percy Miller, better known as New Orleans rapper Master P, spent his hitmaking years in the '90s expanding his business beyond his core No Limit Records label. He successfully invested in clothes, real estate and movies before expanding into sports, which resulted in a costly error demonstrating the inherit risk of capital investment. In 1999 No Limit negotiated a $175,000 contract full of incentives for potential NFL star Ricky Williams, then watched Williams muddle through a year of debilitating injuries, essentially negating his ability to make millions like his peers. Then he left the agency.

"When you look at No Limit Sports, by me not having time to run that, a lot of bad decisions were made," says Master P, head of a new business called P. Miller Enterprises. "Nobody's perfect. When you're a celebrity, people think you don't know what's going on, so a lot of people come to you to invest in stocks, in gold, in oil. A lot of people get caught up, and they lose."

But for every failed attempt there is a success story. Bono struggled with his clothing company EDUN for years before his Elevation Partners made a near $90 million investment in a startup called Facebook. The deal netted the firm a cool $1.4 billion.

Steve Knopper is a Rolling Stone contributing editor and author of MJ: The Genius Of Michael Jackson, out June 28 in paperback.