Case 054Risk management and limit breachesWarm up
A portfolio manager runs Rs 500 crore with a soft stop at minus 5%, where risk is halved, and a hard stop at minus 10%. The book is down 7%. What return recovers the loss, and how does halving risk change the time it takes?
1The situation
A portfolio manager at Sarvatra Multi-Strategy Fund runs a Rs 500 crore book. The firm's drawdown rules are simple: at a loss of 5% from the starting capital the manager must halve risk, and at 10% the book is closed and the capital taken back.
After four difficult months the book is down 7%, at Rs 465 crore, and risk has already been halved. At full risk the manager's strategy has an expected return of about 15% a year with volatility of about 12%; at half risk both halve. Treat these as planning figures, not promises.
2Your task
What return is needed to get back to Rs 500 crore, how long does that take at full and at half risk, and what do the stops buy in exchange?
Quick check
The book is down 7%. What gain takes it back to Rs 500 crore?
Worked solution
Try it on paper, then open one step at a time.
30-second answerThe answer to give first
The book needs a 7.5% gain, which takes about 6 months at full risk but about 12 months at half risk. Rs 35 crore must be earned on Rs 465 crore. Halving risk halves the expected return, so the recovery takes roughly twice as long. In exchange, the chance of hitting the hard stop in the next three months falls from about 59% to about 28%. Restoring full risk once back above minus 5% cuts the wait to about 8 months.
Step 1Why is the recovery return bigger than the loss?
Because the base has shrunk. A shop whose takings fall from Rs 100 to Rs 93 needs a 7.5% rise, not 7%, to get back, since 7% of 93 is only 6.51. Losing Rs 35 crore from Rs 500 crore is 7%, but earning it back on Rs 465 crore is 7.53%. The gap is small at 7% and grows fast: at the hard stop of 10%, recovery needs 11.1%, and a 50% loss needs 100%. That asymmetry is the whole reason drawdown limits exist.
Step 2How long does the recovery take at full and at half risk?
Use the expected return as a planning rate, and say clearly that it is an average, not a path. At 15% a year, 7.53% takes ln(1.0753) over ln(1.15), about 6.2 months. At half risk the expected return is 7.5%, and the same recovery takes about 12.0 months, roughly twice as long. Many desks restore full risk once the book is back above the soft stop. Then the first Rs 10 crore comes at half risk in about 3.5 months and the last Rs 25 crore at full risk in about 4.4 months, 7.9 months in all.
Step 3What does halving risk buy in exchange?
Survival. The book has Rs 15 crore of room before the hard stop, 3.23% of today's capital. Over three months, full-risk volatility of 12% a year is 6%, and half-risk volatility is 3%. Ignoring the small expected gain, the chance of touching the hard stop within three months is about 59% at full risk and about 28% at half risk. A manager who is closed out cannot recover at all, so a slower recovery with a much lower chance of being shut down is usually the better trade.
| Route back to Rs 500 crore | Expected months | Chance of hitting -10% in 3 months |
|---|---|---|
| Full risk throughout | 6.2 | 59% |
| Half risk throughout | 12.0 | 28% |
| Half risk, full again above -5% | 7.9 | 28% at first |
Step 4What is the limitation of this arithmetic?
Two assumptions carry it. The expected return is an average: the actual path will wander, and a recovery that takes six months on paper can take a year or never come. And the probabilities assume returns are roughly normal and independent from day to day, when a book in drawdown often has losing positions that keep losing together. The stops are there precisely because the planning numbers can be wrong, which is also the right answer if the interviewer asks why the manager cannot simply keep full risk and trust the strategy.
Where candidates lose it
Most candidates answer 7% for the recovery. The loss and the repair sit on different bases, so the answer is 7.5%, and the interviewer uses this first step to see whether you know it.
The second miss is treating the soft stop as pure cost. Halving risk slows the way back, but it also halves the chance of being closed out, and a closed book recovers nothing.
What the interviewer asks next
- The book falls to minus 9%. What is the recovery return, and should risk be cut again?
- Why might a firm use a stop on drawdown from peak rather than from starting capital?
- How would you change the rules for a strategy with much fatter tails?
Company names and figures are illustrative.
