Fund Slashes Magnite Stake by $13 Million as Ad Tech Firm Posts $714 Million Revenue Year

By Jonathan Ponciano – Mar 10, 2026 at 6:39PM ESTKey PointsGranahan Investment Management sold 757,249 shares of Magnite in the fourth quarter; the estimated trade value was $12.57 million based on quarterly average pricing.Meanwhile, the quarter-end position value decreased by $33.79 million, reflecting both trading and market price changes.The post-trade stake stood at 3,115,930 shares valued at $50.57 million.On February 17, 2026, Granahan Investment Management disclosed a sale of Magnite (MGNI 3.92%) shares, reducing its stake by 757,249 shares in an estimated $12.57 million transaction based on quarterly average pricing.What happenedAccording to a Securities and Exchange Commission (SEC) filing dated February 17, 2026, Granahan Investment Management decreased its position in Magnite (MGNI 3.92%) by 757,249 shares during the fourth quarter of 2025. The estimated transaction value was $12.57 million, based on the average closing price for the quarter. The quarter-end value of the Magnite stake fell by $33.79 million, which includes both trading activity and price movement effects.What else to knowAfter the sale, Magnite represents 2.17% of Granahan's $2.34 billion in reportable U.S. equity AUM.Top five holdings as of quarter-end:NASDAQ:PRCH: $105.82 million (4.5% of AUM)NYSE:GENI: $86.55 million (3.7% of AUM)NYSE:CRS: $84.12 million (3.6% of AUM)NASDAQ:FTAI: $68.38 million (2.9% of AUM)NASDAQ:VCTR: $67.83 million (2.9% of AUM)As of Thursday, Magnite shares were up about 6% over the past year, well underperforming the S&P 500’s roughly 21% gain in the same period.Company overviewMetricValueRevenue (TTM)$714 millionNet income (TTM)$144.6 millionPrice (as of Tuesday)$13.00Company snapshotMagnite provides an independent sell-side advertising platform, offering applications and services for publishers to manage and monetize digital advertising inventory across CTV, websites, and other digital media properties.The company operates a technology-driven business model, generating revenue primarily through facilitating transactions between digital media sellers and buyers on its platform.It serves publishers, advertisers, agencies, agency trading desks, and demand side platforms in the digital advertising ecosystem.Magnite is a leading independent sell-side advertising platform with a significant presence in the digital advertising market. The company leverages technology to connect publishers and buyers, enabling efficient monetization of digital inventory across multiple channels, including connected TV and online media. Magnite's scale and focus on both supply and demand sides position it as a key facilitator in the evolving programmatic advertising landscape.What this transaction means for investorsMagnite plays an important role in helping publishers monetize ad inventory across connected TV, mobile, and web properties. That’s a positioning that gives it exposure to one of the fastest-growing segments of digital advertising, and recent results show the business steadily scaling.Fourth-quarter revenue reached $205.4 million, bringing full-year revenue to $714 million, up 7% from one year earlier. Profitability also improved meaningfully, with adjusted EBITDA climbing nearly 20% to $232.1 million for the year while margins expanded as the platform handled more ad volume.Perhaps the most important growth engine right now is connected TV. Magnite reported 20% expansion in that segment, which represented roughly 45% of total contribution ex TAC for the year and continues benefiting from the migration of advertising budgets from traditional television into streaming platforms.Against that backdrop, trimming the position modestly keeps the portfolio balanced. With a relatively significant stake in the firm left, it doesn’t seem like there’s been a full loss of conviction.About the AuthorJonathan Ponciano is a contributing stock market analyst at The Motley Fool. He has nearly a decade of experience as a financial journalist, most recently as an editor and senior reporter at Forbes focused on markets, technology, and entrepreneurship. Jonathan has also written for Investopedia and the Los Angeles Business Journal. He holds a dual B.A. in Business Journalism and Economics from the University of North Carolina at Chapel Hill and an M.B.A. from Columbia Business School. A North Carolina native now based in New York City, Jonathan has also lived in Mexico City and Los Angeles.CMFjonponcStocks MentionedMagniteNASDAQ: MGNI$12.99(-3.99%)-$0.54*Average returns of all recommendations since inception. Cost basis and return based on previous market day close.