With several high-value companies going public this year, the question has been: How many millionaires will Silicon Valley mint? How much will go to women is not being asked.

The answer, according to a study released Monday, is: not much.

Carta, an equity management platform, crunched data from more than 300,000 employees at more than 10,000 companies, and found four out of five paper millionaires are men.

The jobs that land the biggest equity packages tend to be held by men in C-suite roles, said Emily Kramer, Carta's vice president of marketing. "As wealth goes up, the percentage of millionaires who are women goes down because they are not CEOs, CFOs or founders," she said.

Chief marketing officers, the most common executive role held by women, have the lowest median equity award, 39% less than that of chief financial officers, who tend to get the most generous packages after CEOs.

Carta last year found women in Silicon Valley held 47 cents for every dollar of equity that men did. Carta this year found a slight improvement: Women hold 49 cents for every dollar in stock options that men do, a 2% increase. Women make up more than a third of all employees, but only hold 20% of equity wealth, it found.

While most equity ends up being worth nothing, when a startup goes public or gets acquired, stock grants can result in a big payday, creating the next class of angel investors and entrepreneurs. And even with underwhelming valuations from tech companies this year, underrepresented employees are getting the "short end of the stick" and become "collateral damage," said Henry Ward, CEO of Carta.

The gender equity gap exists for a variety of reasons. Early employees often get better stock options than those who join later, and younger companies tend to have smaller proportions of women. There's also a lack of representation on founding teams. Women make up only 13% of all founders in the data pulled by Carta, and female-founded teams got only 2.2% of venture funding last year.

Women also say they don't know what to ask for during opaque salary negotiations. One woman who worked for a unicorn startup, who asked not to be identified, said she didn't know to ask for refresh grants after getting promoted several times. When the company went public, she ended up getting $20,000 (before taxes); she calculates she could've been a millionaire.