Janus Henderson Enterprise Fund Class D (JANEX) is an open-end mutual fund managed by Janus Henderson Investors that seeks long-term growth of capital by investing primarily in common stocks selected for their growth potential, with at least 50% of its equity assets normally allocated to medium-sized companies whose market capitalizations fall within the range of the Russell Midcap Growth Index; the fund emphasizes sustainable, long-duration growth companies featuring strong competitive advantages and large addressable markets, while avoiding rapid but unsustainable short-term growth profiles, resulting in a portfolio heavily weighted toward sectors such as technology (approximately 34%), industrials (16%), healthcare (15%), and financial services (12%), with primary exposure to U.S. stocks (75%) supplemented by non-U.S. holdings including Canada (13%) and Eurozone (3%). The fund offers share classes including Class D with a net expense ratio of 0.79%, minimum initial investment of $2,500, and daily pricing, supported by a specialized team of portfolio managers like Brian Demain (since 2007) and Philip Cody Wheaton (since 2016) backed by dedicated small- and mid-cap research analysts. Headquartered at 151 Detroit Street in Denver, Colorado, within the structure of Janus Henderson Group plc—which resulted from the 2017 merger of Janus Capital (founded 1969) and Henderson Global Investors (roots in 1934)—the fund operates as part of Janus Investment Fund and targets individual and institutional investors primarily in the United States. Launched on September 1, 1992, it manages total net assets of approximately $2.51 billion for the Class D shares within the broader fund complex exceeding $23 billion. Recent developments at the parent Janus Henderson Group include a multifaceted strategic partnership with The Guardian Life Insurance Company in 2025, adding $400 million in seed capital for fixed income ETFs like the asset-backed securities ETF (JABS) and expanding fixed income assets under management to $142 billion; acquisitions of Victory Park Capital (October 2024) for global private credit, NBK Capital Partners (September 2024) for emerging markets private investments, and Tabula Investment Management (2024) for European ETFs; a 2023 joint venture with Privacore Capital for alternative investments distribution; and the launch of eight new ETFs globally in 2025 amid record group AUM of $457.3 billion as of Q2 2025. In October 2025, Janus Henderson received a non-binding acquisition proposal from Trian and General Catalyst, which a special board committee is evaluating.