MFS Research Fund Class A (MFRFX) is an open-end mutual fund managed by MFS Investment Management that seeks capital appreciation by investing primarily in equity securities, including common stocks, depositary receipts, and other equity-linked instruments of U.S. and foreign issuers. The fund employs a research-driven, analyst-run strategy focused on bottom-up stock selection across industries and styles; it maintains a diversified, sector-neutral portfolio relative to the S&P 500 Index, with heavy emphasis on technology (35.61%), financial services (12.75%), capital goods (12.74%), and consumer cyclicals (10.40%) as of October 31, 2025; top holdings include NVIDIA Corp, Microsoft Corp, Apple Inc, Amazon.com Inc, and Alphabet Inc Class A. It targets long-term growth-oriented companies of varying market capitalizations, primarily large-cap U.S. equities (weighted average market cap of $1,469.7 billion), with minor exposures to Canada (1.13%) and Sweden (1.15%); the fund holds 93 issues, 99.02% in stocks and 0.98% in cash equivalents, with a portfolio turnover of 43.12%. Launched on October 13, 1971, and headquartered in Boston, Massachusetts, the fund manages net assets of $8.27 billion as of October 31, 2025, with a net expense ratio of 0.77% and a maximum front-end sales charge of 5.75% for Class A shares. No major acquisitions, partnerships, funding rounds, new product launches, or strategic reorganizations have been reported for the fund in the last 1-2 years; it continues to operate under stable management with recent performance showing an 18.80% annual return at NAV for 2024, trailing the S&P 500's 25.02%.