Suppose I am invested in the same fund for the first 200 days in 2013, some combination of 150 days in 2014, and the last 100 days in 2015. Further suppose that geometrically linking the daily returns over every day invested gives a cumulative return of 10% over the total 450 days invested during this 3 year time frame.
What is the annualized return in this case?
A couple possibilities seem reasonable:
Annualize only over days invested: $$(1+10\%)^{365/450} - 1 \approx 8.037\%$$
Annualize over the entire time frame: $$(1+10\%)^{1/3} - 1 \approx 3.228\%$$
Is one of these very different answers the standard or is it entirely context dependent?