Pro-Rata Rightsとは何ですか？

Pro-rata rights (also called pre-emptive rights or participation rights) give an existing investor the option — but not the obligation — to invest in a company's future funding rounds in an amount sufficient to maintain their current ownership percentage. If an investor owns 8% of a company and the company raises a new round, the investor with pro-rata rights can invest enough in that round to retain their 8% stake after dilution.

Pro-rata rights are negotiated as part of the initial investment documents and are typically included in investor rights agreements for lead investors and sometimes for significant early backers. They are almost always time-limited (the investor must decide within a set window, often 10–20 days after receiving the round notice) and may apply only to the investor's 'pro-rata share' rather than any amount they wish to invest. Super pro-rata rights — the ability to invest more than one's proportional share — are occasionally negotiated by larger or more strategically valuable investors.

From the investor's perspective, pro-rata rights are a critical value protection mechanism in venture investing. The venture math often works out such that the follow-on investments in breakout companies generate as much or more return than the initial check. Missing the ability to participate in a Series B for a company growing 200% YoY is a significant economic loss for an early-stage fund. As a result, pro-rata rights are fiercely negotiated in competitive seed rounds.