In early March, CEO Evan Spiegel received a hefty stock bonus worth about $750 million on completion of the company's initial public offering.
But on Wednesday, a poor reception for Snap's first earnings report wiped out more than that amount of his stake in the company.
Snap fell short of Wall Street expectations for revenue and user growth in the first quarter, sending its shares down $5.35, or roughly 23 percent, to $17.66 in after-hours trading.
At that level, they're hovering just above their IPO price of $17.
If that same price drop is sustained in regular trading Thursday, it will cost Spiegel more than $1.3 billion in the space of
At the time of the IPO, both men owned 210.97 million shares, including 97.16 million of Class A shares, 5.86 million of Class B and 107.94 million of Class C. Spiegel was granted an additional 37.4 million shares upon conclusion of the IPO.
Given the size of their stakes, any $5 drop in Snap's stock price will slash the value of their holdings by over $1 billion.
Still, even if the shares drop to $17, their holdings will be worth more than $3.5 billion each.
The company's earliest venture capital investors, Benchmark Capital and Lightspeed Venture Partners, are also in line for a big haircut when markets open on Thursday.
A $5 drop in Snap will cost Benchmark $604 million and Lightspeed $410 million, based on their post-IPO stakes.
Disclosure: CNBC parent NBCUniversal is an investor in Snap.