Putnam Sustainable Leaders Fund Class Y (PNOYX) is an open-end mutual fund that seeks long-term capital appreciation by investing primarily in common stocks of mid- and large-cap U.S. companies, with a focus on those demonstrating leadership in key sustainability issues that are financially material to their business context; it normally invests at least 80% of its net assets in these sustainable leaders, integrating forward-looking sustainability analysis with fundamental equity research; the portfolio emphasizes growth-oriented large-cap stocks across sectors such as technology, healthcare, and industrials, benchmarked against the S&P 500 Index and a Putnam Sustainable Leaders Linked Benchmark, with a portfolio turnover of 44% and annual dividend distributions. The Class Y shares, offered without sales charges to institutional and certain qualified investors, carry a net expense ratio of 0.62% and a minimum initial investment of $0; the fund features a concentrated portfolio of approximately 56 issuers, with significant allocations to mega-cap companies (over $155.9 billion market cap representing about 66% of assets), non-U.S. stocks (10.69%), and cash equivalents; it is classified in the Morningstar Large Growth category and Lipper Large-Cap Core Funds peer group. Managed since 2018 by Katherine Collins, with Stephanie Dobson since 2018 and Rob Forker since January 2025, the fund benefits from Putnam's dedicated sustainable investing team embedded within its equity research and quantitative groups. Launched on August 31, 1990, with Class Y shares introduced July 19, 1994, the fund is domiciled in the United States and managed by Putnam Investments, founded in 1937 and headquartered in Boston, Massachusetts; Putnam operates globally with offices in London, Tokyo, and other locations, and became a subsidiary of Franklin Templeton following the completion of Franklin Resources' acquisition of Putnam from Great-West Lifeco on January 1, 2024, enhancing distribution capabilities and integration with Franklin Templeton's $1.55 trillion AUM platform. Recent developments include the addition of portfolio manager Rob Forker in January 2025 and the merger of Putnam Investments Limited into Franklin Templeton Investment Management Limited effective November 1, 2024, alongside Franklin Templeton's extension of Putnam's capabilities, including sustainable strategies, to international clients in 2025; as of late 2025, the fund manages total net assets of approximately $6.74 billion.