"Many of my colleagues argue that 15% a quarter sums to 60% annually (ignoring geometric linking which cannot apply since there is no compounding). I have a problem with this because the money invested is four distinct unrelated transactions and if you divide the total gain by the sum invested you would get 15%"
When I first considered this problem I focused only on a single execution, to determine the annual equivalent (recognizing that it's generally inappropriate to annualize for periods less than a year). If we treat this as an event for a quarter, then the process is pretty simple:
- Add 1 to the return (1.15)
- Raise it to the inverse of the period expressed in years (1/0.25)
- Subtract 1.
If the ability to generate a return quarterly is 15%, then we could geometrically link four quarterly returns of 15% each:
- Add 1 to each return (1.15)
- Multiply them together
- Subtract 1.
p.s., The same day I got this e-mail and did the analysis, a technician came to my home to winterize the sprinkler system. The cost for the service? $74.90. Kind of weird, right?
p.p.s., If you think this is the last word on this subject, you'll be pleased to learn that we will address this at much greater length in the November newsletter. As you'll see, depending on one's perspective, we can get different answers!