Vault returns are initially benchmarked against "1". For every period thereafter, the benchmark is reset to what is known as a High Water Mark (HWM). The HWM is the product GAV at the time the performance fees are paid out.
If you receive subscribers when GAV is below HWM, they will pay zero performance fees until GAV is back above the HWM.
Subscribe who enter when the product is above HWM, they will pay no fees if the fund ends the period below HWM.