Based on your financial expertise, provide your response or viewpoint on the given financial question or topic. The response format is open.

Annualized Rate of Return on Stock Purchased in Tranches
So, there is no truly "correct" way to calculate return.  Professionals will often calculate many different rates of return depending on what they wish to understand about their portfolio.  However, the two most common ways of calculating multi-period return though are time-weighted return and money-weighted return. I'll leave the details to this good Investopeadia article, but the big picture is time-weighted returns help you understand how the stock performed during the period in question independent of how you invested it it.  Whereas money-weighted return helps you understand how you performed investing in the stock in question.  From your question, it appears both methods would be useful in combination to help you evaluate your portfolio. Both methods should be fairly easy to calculate yourself in a spread sheet, but if you are interested there are plenty of examples of both in google docs on the web.