I'm trying to understand why the total return (return including dividends) that I get from calculating return using adjusted close price, does not equal the total return calculated in another manner.
My example is SNMP in the month of Aug 2018 (simply because it has a large price movement and pays a large dividend, so differences get amplified).
Looking at adjusted prices from yahoo (adjusted prices match Bloombergs) I calculate the total return as
(9.25 / 11.2570) - 1 = -17.83%
To compare I calculate the total return I would have experienced if I had invested $100 on 7/31.
Start = 100 PnL from unadjusted price change = 100 * ((9.25 / 11.75) - 1) = -21.2765 PnL from Div = (100 / 11.75) * 0.451 = 3.8383 PnL from Div reinvestment = 3.8383 * ((9.25 / 9.95) - 1) = -0.2700 End = 100 - 21.2765 + 3.8383 - 0.2700 = 82.2918 % Ret = (82.2918 / 100) - 1 = -17.71%
This matches the total return I get from Bloomberg and from https://www.dividendchannel.com/drip-returns-calculator/. But not the total return I calculated using adjusted prices above. The question is why not?
I dont think this is just a rounding error as the adjusted open price appears to have 4 digits of accuracy, and I have to tweak by more than 0.01 to make it match.