hello denis, pls note following clarifications of the case. Annualised returns mean pro rata per annum in this case. The amounts haven't been invested exactly for an yr, however the returns have to be indicated as 'per annum' in percentage. So 73.11% annualized returns on 100,000 for 10 months means the investor actually got 62,350 in return. now at this stage this return on investment (62,350) is paid out to the investor and does not form a part of invested sum for the next 5 month period. In short this is how it works: 100,000 invested for 10 months, 62350 paid out to the investor & 100,000 capital retained with the firm at the end of 10 month period. Investor invests another 300,000, so now the firm has 400,000 of the investor which the firm keeps for 5 months and returns of 39,200 is paid out to the investor at the end of these 5 months, again the capital of 400,000 is retained by the firm. Investor invests another 600,000, so now the firm has 1,000,000 of the investor which the firm keeps for a 5 month period. At the end of this period, the firm pays out 89,700 to the investor. At this point the investment case ends, firm also returns the total capital invested back to the investor (1,000,000). Now the firm wants to declare how much returns the investor got in percent per annum without the complications of an investment made in stages. Say for example..."Our firm gives 63% per annum to our investors!" 63%5 month perio and does n from the