I understand how to calculate the Annualized return on a stock when I have single purchase ie
(principal + gain/principal) ^ (365/days) - 1
but how is it calculated when I have multiple buys and sells over a time period?
Treat each transaction as separate, with its own principal, its own gain, and its own number of days. Then the total annualized return is just a weighted average of each annualized return, with the weighting related to the number of shares in that transaction.
Since Brad answered with a great reply, I'd like to offer another comment: Be careful with the results. Annualized returns of short term trading can produce some crazy results. For example, a 10% gain in a week isn't unheard of for individual stocks, but (1.1)^52 = 142. or a 14,100% return. This may be obvious, but may help those who aren't so familiar with the numbers to understand that data running less than a year isn't going to provide as much useful conclusion as longer term. Note: Even a year doesn't really reflect success in a given strategy.
Thank you for your interest in this question.
Because it has attracted low-quality or spam answers that had to be removed, posting an answer now requires 10 reputation on this site (the association bonus does not count).
Would you like to answer one of these unanswered questions instead?