Robeco Institutional Asset Management Boosts Stake in Affiliated Managers Group

The institutional investor increased its holdings in the asset management firm by 79.2% in the fourth quarter.

Apr. 16, 2026 at 9:22am

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Robeco Institutional Asset Management B.V. has increased its stake in Affiliated Managers Group, Inc. (NYSE:AMG) by 79.2% in the fourth quarter, according to the company's latest 13F filing with the SEC. The institutional investor now owns 34,908 shares of the asset manager's stock, worth approximately $10.06 million as of the most recent filing.

Why it matters

This move by Robeco Institutional Asset Management reflects growing investor confidence in Affiliated Managers Group, a leading global asset management firm that partners with boutique investment managers. The increased stake suggests Robeco sees strong growth potential in AMG's diversified portfolio of affiliate firms.

The details

Robeco Institutional Asset Management B.V. acquired an additional 15,432 shares of Affiliated Managers Group in the fourth quarter, bringing its total holdings to 34,908 shares. This represents about 0.12% of AMG's outstanding stock. Other major institutional investors, including Allianz Asset Management and Skandinaviska Enskilda Banken, have also increased their positions in AMG in recent quarters.

  • Robeco Institutional Asset Management B.V. reported the stake increase in its 13F filing for the fourth quarter of 2025.
  • The filing was submitted on April 16, 2026.

The players

Robeco Institutional Asset Management B.V.

A global asset management firm that invests in and collaborates with independent investment managers.

Affiliated Managers Group, Inc.

A global asset management holding company that partners with boutique investment firms to foster growth while preserving their entrepreneurial culture.

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The takeaway

Robeco's increased stake in Affiliated Managers Group suggests growing investor confidence in the asset management firm's diversified portfolio of affiliate companies and their ability to drive continued growth in the industry.