See what multiple funding rounds actually do to your ownership, not just this one

You are modeling cap table dilution mechanics across multiple future funding rounds. You compute what each round does to ownership percentages. You do not advise on whether to raise, at what valuation, or whether a given amount of dilution is acceptable — that depends on context you don't have.

CONTEXT
Current cap table (holder: percentage): Founder A: 42%, Founder B: 38%, existing option pool: 10%, seed investors: 10%
Planned or hypothetical future rounds, each with a raise amount and pre-money valuation: Series A: raise $6,000,000 at $18,000,000 pre-money. Series B (2 years later): raise $15,000,000 at $50,000,000 pre-money.
Whether an option pool refresh is planned at any of these rounds, and its target size: Series A includes a pool refresh to bring the pool back up to 12% pre-money
Specific question about dilution you actually want answered: After both rounds, what percentage will the two founders combined actually hold?

SINGLE-ROUND MECHANICS
For the first round in Series A: raise $6,000,000 at $18,000,000 pre-money. Series B (2 years later): raise $15,000,000 at $50,000,000 pre-money., show the arithmetic: new investor ownership = raise ÷ post-money valuation (pre-money + raise), and the resulting dilution to every existing holder in Founder A: 42%, Founder B: 38%, existing option pool: 10%, seed investors: 10%, proportional to their current stake unless Series A includes a pool refresh to bring the pool back up to 12% pre-money changes that.

OPTION POOL REFRESH MECHANIC
If Series A includes a pool refresh to bring the pool back up to 12% pre-money applies, show explicitly that a pre-money option pool refresh dilutes only existing shareholders (not the incoming investor), since the pool is typically carved out of the pre-money valuation before the new investor's ownership percentage is calculated — state this mechanic plainly, since it's a frequently misunderstood point that founders often don't realize hits them disproportionately relative to the round's headline dilution number.

COMPOUNDING ACROSS ROUNDS
Run the same mechanics sequentially across every round in Series A: raise $6,000,000 at $18,000,000 pre-money. Series B (2 years later): raise $15,000,000 at $50,000,000 pre-money., showing cumulative founder ownership after each round, not just the final number — the compounding effect across multiple rounds of dilution is easy to underweight intuitively when only looking at one round at a time.

DIRECT ANSWER
Answer After both rounds, what percentage will the two founders combined actually hold? directly and numerically using the model built above.

MANDATORY CLOSING LINE
End with this exact line, unmodified: "These are dilution mechanics and arithmetic only, not investment advice — a lawyer or startup-focused accountant should review actual terms before you rely on any of these numbers."

OUTPUT FORMAT
Single-Round Mechanics, Option Pool Refresh Mechanic (if applicable), Compounding Across Rounds (a running ownership table), Direct Answer, then the mandatory closing line.