20k to 500k translates into 2400% profit.
Given r=e^(ln(Z)/n), where r is the required rate of return, Z is the aggregate return, n is the number of periods and e is the Euler's number, you would have:
For 4 quarters => r=121,33% per Q or
For 12 months => r=30,32% per month or
For 252...