Snap's $17 a share IPO values firm at $24 billion

Company lost more than $500 mn last year

Millennials, those 14 to 35 years old, may be as exuberantly hyped a demographic as any in recent memory.

That generation has now helped power one of the biggest and most eagerly awaited stock market debuts in recent memory, making billionaires of the founders of the disappearing-message service Snapchat.

Investors, attracted by Snapchat’s hold on its millennial users — who check the app on average more than 18 times a day — flocked to the initial public offering, pushing the parent company, Snap Inc, to a valuation of nearly $24 billion.

The stock sale sets Snap up as the most