Define IRR and MoIC. Which is time-weighted, and why does a fund need to look at both?

What interviewers are really testing

Returns math questions are speed checks with a conceptual trap door. Three things are being graded.

1. Instant MoIC→IRR conversion. "You invest $200 and get $600 in five years, what's the IRR?" must trigger "3x over 5 years, about 25%" in under three seconds, with no pencil. Interviewers deliberately pick the anchor pairs (2x/3yr, 2x/5yr, 3x/5yr) or something adjacent to one so they can watch you interpolate. Reciting Excel syntax (=IRR(...)) instead of the number is an instant tell that you can't operate without a spreadsheet.

2. The conceptual difference. The follow-up is almost always some form of "when would IRR and MoIC give you different answers about the same deal?" Strong candidates immediately reach for timing: a 1.4x flip in one year (40% IRR, thin multiple) versus 3x over 10 years (~12% IRR, great multiple), then state which metric each audience cares about: LPs need multiples to return the fund; IRR drives the preferred-return hurdle and headline marketing.

3. Second-order fluency. Elite interviews push into IRR's flaws: the reinvestment-rate assumption, sub-line and recap engineering, why a deal can show a high IRR yet destroy little-to-no wealth. Volunteering DPI/TVPI as the LP's cross-check, or noting that a dividend recap raises IRR while barely moving MoIC, signals you've thought like an investor rather than memorized formulas.

Delivery matters as much as the answer: state the multiple first, then the conversion, then the caveat if invited. "That's 2.5x over five years, roughly a 20% IRR, strong on both dimensions, though I'd want to know if any of that return came from a recap rather than the exit" is a complete, superday-grade answer. Precision theater (quoting 20.11%) reads worse than a confident "about 20%."

Common traps

Trap 1: Dividing the multiple by the years. Candidates say a 2.0x over 5 years is "20% a year" (100% ÷ 5). IRR compounds: the right answer is about 15%.

Say it out loud: "IRR is a compounding rate, so I can't just divide. Doubling in five years is about a 15% IRR: the Rule of 72 gives 72 divided by 5, roughly 14–15%."

Trap 2: Treating IRR and MoIC as interchangeable quality measures. Saying "the IRR was 45%, so it was a great deal" about a 9-month 1.3x flip ignores that the fund made almost no money.

Say it out loud: "IRR annualizes, so short holds can show spectacular IRRs on trivial dollar profits. I'd always quote the multiple alongside it: a 45% IRR on a 1.3x in nine months returns very little actual capital."

Trap 3: Forgetting interim distributions in MoIC. Computing MoIC as exit equity over entry equity when the sponsor also took a $150M recap dividend understates the return.

Say it out loud: "MoIC is all cash returned over all cash invested: exit proceeds plus any dividends or recap proceeds along the way, divided by the total equity funded."

Trap 4: Claiming a longer hold at the same multiple is 'the same return.' The same 2.5x over 7 years instead of 4 is a materially worse deal.

Say it out loud: "Same multiple, longer hold means a lower IRR: 2.5x is about 26% over four years but only about 14% over seven. Time is the denominator of compounding."

Trap 5: Saying leverage increases IRR with no caveat. Leverage amplifies outcomes in both directions and raises the probability of losing the entire check.

Say it out loud: "Leverage magnifies the equity return if the deal works, and magnifies the loss if it doesn't. It doesn't create value; it concentrates the outcome on a smaller equity base and adds fixed obligations."

Trap 6: Quoting IRR to two decimals from mental math. False precision signals discomfort, not rigor.

Say it out loud: "That's roughly a 25% IRR (3x over five years is the standard anchor) and I'd sharpen it in the model if we needed the exact figure."