Ask HN: How the hell Zuck holds 28.4% after all those rounds from VCs?

In every round of financing it's not only about money raised and valuation as many may think; but the story is way more complicated. Especially because of all the pro-rata rights accumulated by investors over time, the option pool for employees, etc.

This would have diluted Zuck and the other founders in a more substantial way.

Look at Google: 1 seed round + 1 series A and Larry and Sergey have only 10% each. Or Groupon, Zynga, etc - the common is between 7 and 15% of the company for a founder that approach an IPO.