The BlackRock Mid-Cap Growth Equity Portfolio - Class K Shares (BMGKX) is a mutual fund that focuses on investing in mid-sized companies with strong potential for growth. This fund is managed by BlackRock, one of the largest investment management firms in the world. The Class K shares of this fund are designed for institutional investors and have a lower expense ratio compared to other share classes. With a focus on mid-cap growth companies, this fund offers investors the opportunity for long-term capital appreciation.