An AMC has average AUM of Rs 60,000 crore earning a blended 0.55% after distribution costs, and operating costs of Rs 190 crore. What is its operating profit, and what happens to it if markets fall 20%?

Operating profit is Rs 140 crore, and a 20% market fall cuts it to about Rs 74 crore, down 47%. Revenue is Rs 60,000 crore times 0.55%, Rs 330 crore, less Rs 190 crore of costs. When assets fall 20%, revenue falls to Rs 264 crore but costs stay, so profit falls more than twice as fast as assets. An AMC is a fixed-cost business on top of a variable revenue line, and the market sets the revenue.

A tuition centre charges a percentage of each student's fees and pays its teachers a fixed salary; the maths is the same. An AMC's revenue is a percentage of the money it manages, and its costs are mostly people and systems that cost the same whether markets rise or fall. Revenue is Rs 60,000 crore times 0.55%, which is Rs 330 crore. Take off Rs 190 crore of costs and operating profit is Rs 140 crore, a margin of 42% of revenue. Say the 0.55% is after paying distributors, because the gross expense ratio investors pay is higher and a share of it goes to whoever sold the fund.

Shrink the assets and leave the costs alone. Assets fall to Rs 48,000 crore, revenue to Rs 264 crore, and costs stay at Rs 190 crore. Operating profit falls from Rs 140 crore to Rs 74 crore, a drop of 47% for a 20% fall in assets, so profit moves about 2.4 times as far as the market. This is operating leverageThe way a business with mostly fixed costs sees its profit change by a larger percentage than its revenue, in both directions., and it is the whole character of an AMC: wonderful in a rising market, brutal in a falling one. The breakeven is worth stating too: costs of Rs 190 crore need about Rs 34,545 crore of assets at 0.55%, so a fall of about 42% would take the AMC to zero operating profit.

Two refinements the interviewer will like. First, some costs do move: distributor trail is already out of the 0.55%, but bonuses and some marketing shrink in a bad year. If a fifth of costs fall with assets, costs drop to about Rs 182 crore and profit to about Rs 82 crore, down 42% instead of 47%. Second, and worse, investors tend to withdraw after falls, so assets fall by more than the market: a 20% fall plus 5% net outflows takes assets to about Rs 45,600 crore and profit to about Rs 61 crore, down 57%. Debt and liquid funds would cushion the mix, because their assets do not fall with equity, which is one reason AMCs want a broad lineup. The honest limit is that the 0.55% is itself a function of mix: a fall that shifts investors from equity to liquid funds lowers the blended yield as well as the assets.

That an AMC's profit is a leveraged bet on the market it does not control, and that its managers spend their time on the three things they do control. Costs, which decide how far the market can fall before profit disappears; mix, because debt and liquid assets steady revenue; and flows, because an AMC that keeps gathering assets in a flat market grows while its rivals shrink. An interviewer who hears those three after the arithmetic knows you understood the arithmetic.