Example:
ETF A has a TER of 5%, ETF B has a TER
of 1%
ETF A = ETF B in terms
if performancees (they track exactly the same assets). Lets suppose that the ETFs do a +100% in a year. If we subtract the TER, at the end of the year ETF A will have a performance of 95% increase, while ETF B of 99%.