Company: MGRE
Filing Date: 2025-02-28
Form Type: S-3ASR
Source: 0001193125-25-042543
Chunk: 2

Company: AFFILIATED MANAGERS GROUP, INC.
Filing Date: 2025-02-28
Form: S-3ASR
Chunk 2
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 shares,
warrants, or other securities offered by this prospectus, the related prospectus supplement will disclose the exchange or market on which the securities will be listed, if any, or where we have made an application for listing, if any.

This prospectus may be used to offer and sell securities only if accompanied by a prospectus supplement for those securities.

Investing in these securities involves certain risks. Before making a decision to invest in these securities, you should refer to the risk factors included in our periodic reports, in prospectus supplements relating to specific offerings and in other information that we file with the Securities and Exchange Commission (the “SEC”). See “ Risk Factors” on page 2.

The address of AMG’s principal executive offices is 777 South Flagler Drive, West Palm Beach, Florida 33401 and the telephone number at the
principal executive offices is (800) 345-1100.

Neither the SEC nor any other regulatory body has approved or disapproved of these securities or passed upon the accuracy or adequacy of this prospectus. Any representation to the contrary is a criminal offense.

The date of this prospectus is February 28, 2025

TABLE OF CONTENTS

| ABOUT THIS PROSPECTUS                                      |     |  1 |
| RISK FACTORS                                               |     |  2 |
| FORWARD-LOOKING STATEMENTS                                 |     |  3 |
| WHERE YOU CAN FIND MORE INFORMATION                        |     |  4 |
| THE COMPANY                                                |     |  5 |
| USE OF PROCEEDS                                            |     |  6 |
| DESCRIPTION OF THE DEBT SECURITIES                         |     |  7 |
| DESCRIPTION OF COMMON STOCK                                |     |  8 |
| DESCRIPTION OF PREFERRED STOCK                             |     | 10 |
| DESCRIPTION OF DEPOSITARY SHARES                           |     | 11 |
| DESCRIPTION OF WARRANTS                                    |     | 12 |
| DESCRIPTION OF SUBSCRIPTION RIGHTS                         |     | 13 |
| DESCRIPTION OF STOCK PURCHASE CONTRACTS AND STOCK PURCHASE 
 UNITS                                                      |     | 14 |
| PLAN OF DISTRIBUTION                                       |     | 15 |
| VALIDITY OF SECURITIES                                     |     | 17 |
| EXPERTS                                                    |     | 18 |

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ABOUT THIS PROSPECTUS

Each time we offer securities using this prospectus, we will provide the specific terms and offering prices in a supplement to this
prospectus. The prospectus supplements also may