bull market babies
n. The generation born since 1980 while the stock market has been in a sustained bull market.
Nearly 80 million baby boomers in their late 30s to mid-50s make up half of the workforce and 70 percent of American management. The next wave of Xers is nearly 40 percent smaller.

That means a serious leadership shortfall until Generation Y (a.k.a. the "Echo Boom" or "Bull Market Babies") kicks in with its legion of 72 million.
—Cheryl Hall, “A Gen-X State of Mind,” The Dallas Morning News, July 25, 1999
Back then, it was the Indians versus the colonials. Later, it was the locals versus the Summer Colony, and later still, the social conservatives versus the freewheeling surrealists. Today, it is the yuppies of the 80's pitted against the bull market babies of the 90's.
—Johanna Berkman, “It's the Hamptons as a Battleground,” The New York Times, May 17, 1998
1987 (earliest)
Just as the crash wiped 40 per cent off stock values, it has wiped smiles off the faces of the so-called "bull market babies". Those now smiling are the yuppie haters, relishing the day when pampered youngsters got their come-uppance.
— Turner Parkinson, “Are the Yuppies dead or have they just lost their toys?,” Herald, November 16, 1987