Mirae had heavily betted on Midcap rally of 2017 but 2018 Jan was a peak and miserable hammering in midcap/SC which put them in their own kind of recession.
Check their composition, might likely corroborate and this is all in that 3yr window.
Even today, SC/MC barely reaching break even levels etc. The MC100 and SC indices are still under water by -10%/-20% resp,
In the same period NS, is up 20%
big difference in returns.