Can anyone offer advice as to how I can emulate a Total Expense Ration (annual charge) during back testing. I am back testing ETFs for which an (example) annual charge would be 0.22% per annum. In other tools I can reduce the equity by applying a daily equivalent of the annual charge or alternatively just apply the annual charge to the equity at the start of each new year. I would prefer to do this via the Back Testing settings, but I also understand that an AFL approach may be the only option. Regards,
On every year boundary you can just subtract that 0.22% from bo.Cash field in the custom backtester. Alternatively you could use some negative interest rate, but really, do you need to do that? Would 0.22% per year be anything significant in your account?