Average Annual Growth Rate - AAGR

What Does Average Annual Growth Rate - AAGR Mean?
The average increase in the value of an individual investment or portfolio over the period of a year. It is calculated by taking the arithmetic mean of the growth rate over two annual periods. The average annual growth rate can be calculated for any investment, but will not include any measure of the investment's overall risk, as measured by its price volatility.

Investopedia explains Average Annual Growth Rate - AAGR
Just as the name says, it is the average growth rate. For example, if your portfolio grows 10% one year and 20% the next, your AAGR would be 15%. To this end, fluctuations in the portfolio's rate of return between the beginning of the first year, and the end of the year are not included in the calculations, which may lead to some measurement error.

To reduce any possible measurement error, an analyst can simply take the average price at the beginning and end of the two measurement periods, and use those average prices to determine each year's return, and then the AAGR.