The MFS Aggressive Growth Allocation Fund Class R4 (MAALX) is a mutual fund that aims to provide investors with long-term capital appreciation by investing in a diversified portfolio of growth-oriented stocks and bonds. This fund is designed for investors with a higher risk tolerance and a longer investment horizon. It may also allocate a portion of its assets to alternative investments such as real estate or commodities. The R4 class of this fund typically has lower expenses and a higher minimum investment compared to other classes, making it suitable for larger investors. Overall, MAALX offers a balanced approach to aggressive growth investing, providing potential for high returns while managing risk through diversification.