“They’re getting married, they’re having kids, their college loans are due, they’re responsible for some older member of the family’s healthcare,” Dempster said. “Other things happen. Divorce happens. Poor health happens. And here they are sitting on an incredibly valuable currency that’s illiquid.”

Adding to the anxiousness among those with equity in startups is a drop in valuations for some high-profile companies. Fidelity cut the valuation of Snapchat Inc. by about 25 percent in the third quarter, BlackRock Inc. trimmed the value of storage-company Dropbox Inc. and payments company Square Inc. is seeking an IPO market capitalization that’s significantly lower than its valuation as a privately held company.

There’s no shortage of eager buyers attempting to buy a stake in a hot startup. Some aspiring investors even cold call insiders asking to buy shares.


Strong Demand


“I get probably 10 emails a week from people way out of the Valley, very different professions, nothing to do with the Valley: ‘Hey, I know you’re an investor, can I buy some of your shares?”’ says Sam Altman, president of Y Combinator, an early- stage investor of hundreds in startups. He always says no.

(The Y Combinator startups’ backers include Willett Advisors, the investment arm for the personal and philanthropic assets of Michael R. Bloomberg, the founder of Bloomberg LP.)

Most big-name Silicon Valley startups have organized secondary stock sales for employees, founders and investors. Even at Uber Technologies Inc., where secondary sales have been strictly prohibited, CEO Travis Kalanick said recently that he’d consider creating a process for early employees and investors to sell some shares.

These internal sales are tightly circumscribed, allowing employees to sell 10 percent to 20 percent of their shares, often at a predetermined price based on the company’s most recent valuation. (Early investors typically can sell as much as they want.)


Forward Contracts


But organized sales clearly aren’t meeting all the demand to cash out. Many employees and investors are finding other ways to sell shares on their own. Several companies have sprouted up to help find buyers for their shares. EquityZen, based in New York, offers “forward contracts,” where an employee trades the rights to their stock in exchange for cash now. The company sends out regular e-mails offering stock in companies such as Spotify, AppDyanmics and Chartboost. The sellers “get the cash they are looking for,” said Chief Executive Officer Atish Davda said in an interview.