For an options portfolio, I'd like to calculate return on capital from Jan to Dec. These are monthly options that are held for a few days to months. There's a couple of problems with trying to calculate calendar year returns:
1.) The early months will have low or not returns compared to months such as March - Sep.
2.) The latter months will have options expiring in Jan, Feb, and Mar of the next year.
How do I account for the above issues?