Investors are "betting on the future," when it comes to Snap, Greycroft Managing Director Alan Patricof told CNBC on Tuesday.
"They are assuming a growth rate that some would say is unsustainable."
Snap would have to grow 50 percent a year over the next 10 years just to grow into its valuation today, Patricof said during an interview on CNBC's "Squawk Box."
Needless to say, competition in the social media space is fierce, and there's "a new [app] emerging every day," Patricof said.
On the other hand, people are excited because of Snapchat's success so far, Patricof, who is not an investor in Snap, told CNBC.
"It's hard to take away what they've accomplished — I think Evan [Spiegel] has done a great job."
Patricof said he's "most disappointed" about Snap's no-vote policy, referring to the company's decision to sell investors nonvoting shares.
Shares of Snap continued to fall into Tuesday, trading down 11 percent in the afternoon. On Monday the stock fell below its opening price of $24 for the first time.