Eight Capital raised Fund II with one specific purpose: to write $200K checks instead of $50-100K checks. The reason is not diversification or brand signaling. The reason is pro-rata rights.
Pro-rata rights are the right to invest your proportional share in a company's future rounds, maintaining your ownership percentage. They sound like a footnote. In early-stage YC investing, they are the return driver.
The mechanics
A $100K seed check at a $15M cap gives you 0.67% of the company. The company raises a $20M Series A at a $100M pre-money. Without pro-rata rights, you're diluted from 0.67% to approximately 0.44%. If the company exits at $500M, your $100K returns roughly $2.2M — a 22x multiple.
With pro-rata rights, you can invest another $440K in the Series A to maintain 0.67%. Total invested: $540K. Same exit at $500M: your position is worth $3.35M, plus the $440K Series A position is also worth considerably more. The real difference appears at scale: the one or two breakout companies in a 20-company portfolio are the ones where you want to own more at Series A, not less.
The seed check opens the door. Pro-rata rights let you walk through it again when you know what's on the other side.
Why check size determines whether you get them
Pro-rata rights must be negotiated. The leverage is almost entirely a function of check size. A company raising $1.5M at Demo Day with 40 investors doesn't want to manage 40 pro-rata elections at the Series A. They'll grant pro-rata to investors above a threshold — typically $100-200K or more — and exclude the smaller checks.
This is why Fund I's $50-100K checks often didn't generate pro-rata rights even in the portfolio's strongest performers. Large enough to get allocation, not large enough to get follow-on rights. Fund II's $200K check is designed to clear the threshold where pro-rata becomes negotiable.
The cost of not having them
An Eight Capital Fund I portfolio company raises a Series A at $150M valuation. Fund I's $75K seed check is now worth $300K on marks. The company is headed to a $1B+ exit. Without pro-rata, that seed position gets diluted at Series A, diluted at Series B, diluted at Series C. By exit, the original 0.5% might be 0.1%. The $75K returns $1.2M — good, not great.
$150K in the Series A would have returned another $3M. That missed follow-on isn't a rounding error. In a power law portfolio, the fund-returning companies are exactly the ones where you need more ownership at Series A.
The seed check is not the investment. It's the option to make the real investment when you have information. Pro-rata rights are what converts that option into action. Fund II is built around having that option.