Annual Percentage Rate - APR (%): The real APR is calculated summing the total STEEM amount received during the first 358 days of the year, divided by the the total STEEM POWER amount delegated and multiplied by 100. It is considered that the STEEM POWER undelegation occurs at the 358th day of the year, so the last 7 days of the year are the cooldown period related to the undelegation process at STEEMIT network. This percentage rate is shown in the graph bellow, on a daily basis, and it is calculated multiplying the "STEEM per 1k SP delegation" daily rate by 358, then dividing it by 1000 and finally multiplying the result by 100, to give the value in percentage. The APR calculation considers that the sponsor will not power down its SP.
Annual Internal Rate of Return - IRR (%): Given a collection of 365 pairs (day of the year, STEEM cash flow), the daily internal rate of return follows from the net present value as a function of the rate of return. A rate of return for which this function being zero is the daily internal rate of return. Then, the Annual Internal Rate of Return is calculated based on the daily internal rate of return. The IRR calculation considers that the sponsor will power down its SP in such a manner that at the end of the year all its SP delegated would be converted into STEEM. In order to better understand the cash flow used in this calculation, please click the button "IRR cash flow detail" to open an infograph.