<html>
<head>


  </head>
<body lang="EN-US">
<div style="font-family:Times New Roman;">
<div style="border-bottom:solid windowtext 1.0pt;border-left:none;border-right:none;border-top:solid windowtext 3.0pt;padding:1.0pt 0in 1.0pt 0in;">
<p style="border:none;margin:0in 0in .0001pt;padding:0in;"><font size="1" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
</div>
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="5" face="Times New Roman" style="font-size:18.0pt;font-weight:bold;">UNITED STATES</font></b></p>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="5" face="Times New Roman" style="font-size:18.0pt;font-weight:bold;">SECURITIES AND EXCHANGE COMMISSION</font></b></p>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">WASHINGTON, DC 20549</font></b></p>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="5" face="Times New Roman" style="font-size:18.0pt;font-weight:bold;">FORM&nbsp;8-K</font></b></p>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="3" face="Times New Roman" style="font-size:12.0pt;font-weight:bold;">CURRENT REPORT PURSUANT</font></b></p>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="3" face="Times New Roman" style="font-size:12.0pt;font-weight:bold;">TO SECTION&nbsp;13 OR 15(D)&nbsp;OF THE</font></b></p>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="3" face="Times New Roman" style="font-size:12.0pt;font-weight:bold;">SECURITIES EXCHANGE ACT OF 1934</font></b></p>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Date of report (Date of earliest event reported): <b>August&nbsp;6, 2013</b></font></p>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="5" face="Times New Roman" style="font-size:18.0pt;font-weight:bold;">Affiliated Managers Group,&nbsp;Inc.</font></b></p>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(Exact Name of Registrant as Specified in Its Charter)</font></p>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">Delaware</font></b></p>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(State or Other Jurisdiction of Incorporation)</font></p>
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<div align="center">
<table border="0" cellspacing="0" cellpadding="0" width="100%" style="border-collapse:collapse;width:100.0%;">
<tr>
<td width="48%" valign="top" style="padding:0in 0in 0in 0in;width:48.94%;">
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">001-13459</font></b></p>    </td>
<td width="2%" valign="bottom" style="padding:0in 0in 0in 0in;width:2.14%;">
<p style="margin:0in 0in .0001pt;"><b><font size="2" face="Times New Roman" style="font-size:1.0pt;font-weight:bold;">&nbsp;</font></b></p>    </td>
<td width="48%" valign="top" style="padding:0in 0in 0in 0in;width:48.92%;">
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">04-3218510</font></b></p>    </td>   </tr>
<tr>
<td width="48%" valign="top" style="padding:0in 0in 0in 0in;width:48.94%;">
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(Commission File Number)</font></p>    </td>
<td width="2%" valign="bottom" style="padding:0in 0in 0in 0in;width:2.14%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>    </td>
<td width="48%" valign="top" style="padding:0in 0in 0in 0in;width:48.92%;">
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(IRS Employer Identification No.)</font></p>    </td>   </tr>
<tr>
<td width="48%" valign="top" style="padding:0in 0in 0in 0in;width:48.94%;">
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>    </td>
<td width="2%" valign="bottom" style="padding:0in 0in 0in 0in;width:2.14%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>    </td>
<td width="48%" valign="top" style="padding:0in 0in 0in 0in;width:48.92%;">
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>    </td>   </tr>
<tr>
<td width="48%" valign="top" style="padding:0in 0in 0in 0in;width:48.94%;">
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">600 Hale Street<br>   P.O.&nbsp;Box 1000<br>   Prides Crossing, Massachusetts</font></b></p>    </td>
<td width="2%" valign="bottom" style="padding:0in 0in 0in 0in;width:2.14%;">
<p style="margin:0in 0in .0001pt;"><b><font size="2" face="Times New Roman" style="font-size:1.0pt;font-weight:bold;">&nbsp;</font></b></p>    </td>
<td width="48%" valign="bottom" style="padding:0in 0in 0in 0in;width:48.92%;">
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">01965</font></b></p>    </td>   </tr>
<tr>
<td width="48%" valign="top" style="padding:0in 0in 0in 0in;width:48.94%;">
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(Address of Principal Executive   Offices)</font></p>    </td>
<td width="2%" valign="bottom" style="padding:0in 0in 0in 0in;width:2.14%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>    </td>
<td width="48%" valign="top" style="padding:0in 0in 0in 0in;width:48.92%;">
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(Zip Code)</font></p>    </td>   </tr>  </table>
</div>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">(617) 747-3300</font></b></p>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(Registrant&#146;s Telephone Number,&nbsp;Including Area Code)</font></p>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">N/A</font></b></p>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(Former Name or Former Address, if Changed Since Last Report)</font></p>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Check the appropriate box below if the Form&nbsp;8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (<i>see </i>General Instruction A.2. below):</font></p>
<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<p style="margin:0in 0in .0001pt .5in;"><font size="2" face="Wingdings" style="font-size:10.0pt;">o</font><font size="1" style="font-size:3.0pt;">&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; </font><font size="2" style="font-size:10.0pt;">Written communications pursuant to Rule&nbsp;425 under the Securities Act (17 CFR 230.425)</font></p>
<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Wingdings" style="font-size:10.0pt;">o</font><font size="1" style="font-size:3.0pt;">&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; </font><font size="2" style="font-size:10.0pt;">Soliciting material pursuant to Rule&nbsp;14a-12 under the Exchange Act (17 CFR 240.14a-12)</font></p>
<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Wingdings" style="font-size:10.0pt;">o</font><font size="1" style="font-size:3.0pt;">&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; </font><font size="2" style="font-size:10.0pt;">Pre-commencement communications pursuant to Rule&nbsp;14d-2(b)&nbsp;under the Exchange Act (17 CFR 240.14d-2(b))</font></p>
<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Wingdings" style="font-size:10.0pt;">o</font><font size="1" style="font-size:3.0pt;">&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; </font><font size="2" style="font-size:10.0pt;">Pre-commencement communications pursuant to Rule&nbsp;13e-4(c)&nbsp;under the Exchange Act (17 CFR 240.13e-4(c))</font></p>
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<div style="border-bottom:solid windowtext 3.0pt;border-left:none;border-right:none;border-top:solid windowtext 1.0pt;padding:1.0pt 0in 1.0pt 0in;">
<p style="border:none;margin:0in 0in .0001pt;padding:0in;"><font size="1" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
</div>
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<div style="margin:0in 0in .0001pt;"><hr size="3" width="100%" noshade color="#010101" align="left"></div>
</div>
<!-- SEQ.=1,FOLIO='',FILE='C:\JMS\kyangb\13-12933-4\task6184254\12933-4-ba.htm',USER='Kyangb',CD='Aug  6 14:47 2013' -->

<br clear="all" style="page-break-before:always;">
<div style="font-family:Times New Roman;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<p style="margin:0in 0in .0001pt;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">ITEM&nbsp;8.01</font></b><b><font size="1" style="font-size:3.0pt;font-weight:bold;">&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; </font></b><b><font size="2" style="font-size:10.0pt;font-weight:bold;">Other Events.</font></b></p>
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">On August&nbsp;6, 2013, Affiliated Managers Group,&nbsp;Inc. (the &#147;Company&#148;) filed a registration statement and prospectus supplement following the expiration of its existing registration statement.&#160; The prospectus supplement effectively replaces that filed in August&nbsp;2012, which provided for the sale of up to $400 million in shares of the Company&#146;s common stock.&#160; The Company sold $147.2&nbsp;million under that supplement pursuant to forward sale arrangements (which have not yet been settled), with $252.8&nbsp;million of sales capacity remaining. The Company has no current intention to sell additional shares of common stock at this time.</font></p>
<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">In connection with this prospectus supplement, the Company has entered into initial forward sale agreements and distribution agency agreements with each of Merrill Lynch, Pierce, Fenner&nbsp;&amp; Smith Incorporated, Deutsche Bank Securities Inc., Citigroup Global Markets Inc., Mitsubishi UFJ Securities (USA), Inc., RBC Capital Markets, LLC, Scotia Capital (USA) Inc. and Wells Fargo Securities, LLC (or an affiliate of the same).&#160; The forms of such agreements are attached as Exhibits 10.1 and 10.2 hereto.&#160; In addition, Ropes&nbsp;&amp; Gray LLP issued an opinion regarding the validity of shares to be issued pursuant to forward sale agreements, which is attached as Exhibit 5.1 hereto.</font></p>
<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<p style="margin:0in 0in .0001pt;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">ITEM 9.01</font></b><b><font size="1" style="font-size:3.0pt;font-weight:bold;">&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; </font></b><b><font size="2" style="font-size:10.0pt;font-weight:bold;">Financial Statements and Exhibits.</font></b></p>
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<p style="margin:0in 0in .0001pt .75in;text-indent:-.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(d)</font><font size="1" style="font-size:3.0pt;">&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; </font><font size="2" style="font-size:10.0pt;">Exhibits.</font></p>
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<table border="0" cellspacing="0" cellpadding="0" width="96%" style="border-collapse:collapse;margin-left:.25in;width:96.66%;">
<tr>
<td width="9%" valign="bottom" style="border:none;border-bottom:solid windowtext 1.0pt;padding:0in 0in 0in 0in;width:9.48%;">
<p style="margin:0in 0in .0001pt;"><b><font size="1" face="Times New Roman" style="font-size:8.0pt;font-weight:bold;">Exhibit&nbsp;No.</font></b></p>    </td>
<td width="2%" valign="bottom" style="padding:0in 0in 0in 0in;width:2.6%;">
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="1" face="Times New Roman" style="font-size:1.0pt;font-weight:bold;">&nbsp;</font></b></p>    </td>
<td width="87%" valign="bottom" style="border:none;border-bottom:solid windowtext 1.0pt;padding:0in 0in 0in 0in;width:87.92%;">
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="1" face="Times New Roman" style="font-size:8.0pt;font-weight:bold;">Description</font></b></p>    </td>   </tr>
<tr>
<td width="9%" valign="top" style="border:none;padding:0in 0in 0in 0in;width:9.48%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>    </td>
<td width="2%" valign="bottom" style="padding:0in 0in 0in 0in;width:2.6%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>    </td>
<td width="87%" valign="top" style="border:none;padding:0in 0in 0in 0in;width:87.92%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>    </td>   </tr>
<tr>
<td width="9%" valign="top" style="padding:0in 0in 0in 0in;width:9.48%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">5.1</font></p>    </td>
<td width="2%" valign="bottom" style="padding:0in 0in 0in 0in;width:2.6%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>    </td>
<td width="87%" valign="top" style="padding:0in 0in 0in 0in;width:87.92%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Opinion of Ropes&nbsp;&amp; Gray LLP as to   the validity of the shares to be issued pursuant to each of the Confirmation   Letter Agreements dated August&nbsp;6, 2013 and any subsequent related   Confirmation Letter Agreements.</font></p>    </td>   </tr>
<tr>
<td width="9%" valign="top" style="padding:0in 0in 0in 0in;width:9.48%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>    </td>
<td width="2%" valign="bottom" style="padding:0in 0in 0in 0in;width:2.6%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>    </td>
<td width="87%" valign="top" style="padding:0in 0in 0in 0in;width:87.92%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>    </td>   </tr>
<tr>
<td width="9%" valign="top" style="padding:0in 0in 0in 0in;width:9.48%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">10.1</font></p>    </td>
<td width="2%" valign="bottom" style="padding:0in 0in 0in 0in;width:2.6%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>    </td>
<td width="87%" valign="top" style="padding:0in 0in 0in 0in;width:87.92%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Form&nbsp;of Confirmation Letter Agreement,   dated as of August&nbsp;6, 2013.</font></p>    </td>   </tr>
<tr>
<td width="9%" valign="top" style="padding:0in 0in 0in 0in;width:9.48%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>    </td>
<td width="2%" valign="bottom" style="padding:0in 0in 0in 0in;width:2.6%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>    </td>
<td width="87%" valign="top" style="padding:0in 0in 0in 0in;width:87.92%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>    </td>   </tr>
<tr>
<td width="9%" valign="top" style="padding:0in 0in 0in 0in;width:9.48%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">10.2</font></p>    </td>
<td width="2%" valign="bottom" style="padding:0in 0in 0in 0in;width:2.6%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>    </td>
<td width="87%" valign="top" style="padding:0in 0in 0in 0in;width:87.92%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Form&nbsp;of Distribution Agency Agreement,   dated as of August&nbsp;6, 2013.</font></p>    </td>   </tr>  </table>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">2<a name="PB_2_093920_7056"></a></font></p>
<div style="margin:0in 0in .0001pt;"><hr size="3" width="100%" noshade color="#010101" align="left"></div>
</div>
<!-- SEQ.=1,FOLIO='2',FILE='C:\JMS\kyangb\13-12933-4\task6184254\12933-4-ba.htm',USER='Kyangb',CD='Aug  6 14:47 2013' -->

<br clear="all" style="page-break-before:always;">
<div>
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">SIGNATURES</font></b></p>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<p style="margin:0in 0in .0001pt;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.</font></p>
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<table border="0" cellspacing="0" cellpadding="0" width="100%" style="border-collapse:collapse;width:100.0%;">
<tr>
<td width="49%" valign="top" style="padding:0in 0in 0in 0in;width:49.84%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>    </td>
<td width="50%" colspan="3" valign="top" style="padding:0in 0in 0in 0in;width:50.16%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">AFFILIATED MANAGERS GROUP,&nbsp;INC.</font></p>    </td>   </tr>
<tr>
<td width="49%" valign="top" style="padding:0in 0in 0in 0in;width:49.84%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>    </td>
<td width="50%" colspan="3" valign="top" style="padding:0in 0in 0in 0in;width:50.16%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>    </td>   </tr>
<tr>
<td width="49%" valign="top" style="padding:0in 0in 0in 0in;width:49.84%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Date:&nbsp;August&nbsp;6, 2013</font></p>    </td>
<td width="50%" colspan="3" valign="top" style="padding:0in 0in 0in 0in;width:50.16%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>    </td>   </tr>
<tr>
<td width="49%" valign="top" style="padding:0in 0in 0in 0in;width:49.84%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>    </td>
<td width="4%" valign="top" style="padding:0in 0in 0in 0in;width:4.62%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">By:</font></p>    </td>
<td width="45%" colspan="2" valign="top" style="border:none;border-bottom:solid windowtext 1.0pt;padding:0in 0in 0in 0in;width:45.54%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">/s/ John Kingston,&nbsp;III</font></p>    </td>   </tr>
<tr>
<td width="49%" valign="top" style="padding:0in 0in 0in 0in;width:49.84%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>    </td>
<td width="4%" valign="top" style="padding:0in 0in 0in 0in;width:4.62%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>    </td>
<td width="6%" valign="top" style="border:none;padding:0in 0in 0in 0in;width:6.66%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Name:</font></p>    </td>
<td width="38%" valign="top" style="border:none;border-top:solid windowtext 1.0pt;padding:0in 0in 0in 0in;width:38.88%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">John Kingston,&nbsp;III</font></p>    </td>   </tr>
<tr>
<td width="49%" valign="top" style="padding:0in 0in 0in 0in;width:49.84%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>    </td>
<td width="4%" valign="top" style="padding:0in 0in 0in 0in;width:4.62%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>    </td>
<td width="6%" valign="top" style="padding:0in 0in 0in 0in;width:6.66%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Title:</font></p>    </td>
<td width="38%" valign="top" style="padding:0in 0in 0in 0in;width:38.88%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Vice Chairman,</font></p>    </td>   </tr>
<tr>
<td width="49%" valign="top" style="padding:0in 0in 0in 0in;width:49.84%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>    </td>
<td width="4%" valign="top" style="padding:0in 0in 0in 0in;width:4.62%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>    </td>
<td width="6%" valign="top" style="padding:0in 0in 0in 0in;width:6.66%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>    </td>
<td width="38%" valign="top" style="padding:0in 0in 0in 0in;width:38.88%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">General Counsel and Secretary</font></p>    </td>   </tr>  </table>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">3<a name="PB_3_094059_5335"></a></font></p>
<div style="margin:0in 0in .0001pt;"><hr size="3" width="100%" noshade color="#010101" align="left"></div>
</div>
<!-- SEQ.=1,FOLIO='3',FILE='C:\JMS\kyangb\13-12933-4\task6184254\12933-4-ba.htm',USER='Kyangb',CD='Aug  6 14:47 2013' -->

<br clear="all" style="page-break-before:always;">
<div>
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">EXHIBIT&nbsp;INDEX</font></b></p>
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<table border="0" cellspacing="0" cellpadding="0" width="100%" style="border-collapse:collapse;width:100.0%;">
<tr>
<td width="11%" valign="bottom" style="border:none;border-bottom:solid windowtext 1.0pt;padding:0in 0in 0in 0in;width:11.5%;">
<p style="margin:0in 0in .0001pt;"><b><font size="1" face="Times New Roman" style="font-size:8.0pt;font-weight:bold;">Exhibit&nbsp;No.</font></b></p>    </td>
<td width="2%" valign="bottom" style="padding:0in 0in 0in 0in;width:2.14%;">
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="1" face="Times New Roman" style="font-size:1.0pt;font-weight:bold;">&nbsp;</font></b></p>    </td>
<td width="86%" valign="bottom" style="border:none;border-bottom:solid windowtext 1.0pt;padding:0in 0in 0in 0in;width:86.36%;">
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><b><font size="1" face="Times New Roman" style="font-size:8.0pt;font-weight:bold;">Description</font></b></p>    </td>   </tr>
<tr>
<td width="11%" valign="top" style="border:none;padding:0in 0in 0in 0in;width:11.5%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>    </td>
<td width="2%" valign="bottom" style="padding:0in 0in 0in 0in;width:2.14%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>    </td>
<td width="86%" valign="top" style="border:none;padding:0in 0in 0in 0in;width:86.36%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>    </td>   </tr>
<tr>
<td width="11%" valign="top" style="padding:0in 0in 0in 0in;width:11.5%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">5.1</font></p>    </td>
<td width="2%" valign="bottom" style="padding:0in 0in 0in 0in;width:2.14%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>    </td>
<td width="86%" valign="top" style="padding:0in 0in 0in 0in;width:86.36%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Opinion of Ropes&nbsp;&amp; Gray LLP as to   the validity of the shares to be issued pursuant to each of the Confirmation   Letter Agreements dated August&nbsp;6, 2013 and any subsequent related   Confirmation Letter Agreements.</font></p>    </td>   </tr>
<tr>
<td width="11%" valign="top" style="padding:0in 0in 0in 0in;width:11.5%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>    </td>
<td width="2%" valign="bottom" style="padding:0in 0in 0in 0in;width:2.14%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>    </td>
<td width="86%" valign="top" style="padding:0in 0in 0in 0in;width:86.36%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>    </td>   </tr>
<tr>
<td width="11%" valign="top" style="padding:0in 0in 0in 0in;width:11.5%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">10.1</font></p>    </td>
<td width="2%" valign="bottom" style="padding:0in 0in 0in 0in;width:2.14%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>    </td>
<td width="86%" valign="top" style="padding:0in 0in 0in 0in;width:86.36%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Form&nbsp;of Confirmation Letter Agreement,   dated as of August&nbsp;6, 2013.</font></p>    </td>   </tr>
<tr>
<td width="11%" valign="top" style="padding:0in 0in 0in 0in;width:11.5%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>    </td>
<td width="2%" valign="bottom" style="padding:0in 0in 0in 0in;width:2.14%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>    </td>
<td width="86%" valign="top" style="padding:0in 0in 0in 0in;width:86.36%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>    </td>   </tr>
<tr>
<td width="11%" valign="top" style="padding:0in 0in 0in 0in;width:11.5%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">10.2</font></p>    </td>
<td width="2%" valign="bottom" style="padding:0in 0in 0in 0in;width:2.14%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>    </td>
<td width="86%" valign="top" style="padding:0in 0in 0in 0in;width:86.36%;">
<p style="margin:0in 0in .0001pt;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Form&nbsp;of Distribution Agency Agreement,   dated as of August&nbsp;6, 2013.</font></p>    </td>   </tr>  </table>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
<p align="center" style="margin:0in 0in .0001pt;text-align:center;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">4<a name="PB_4_094142_5796"></a></font></p>
<div style="margin:0in 0in .0001pt;"><hr size="3" width="100%" noshade color="#010101" align="left"></div>
</div>
<!-- SEQ.=1,FOLIO='4',FILE='C:\JMS\kyangb\13-12933-4\task6184254\12933-4-ba.htm',USER='Kyangb',CD='Aug  6 14:47 2013' -->

</body>
</html>
[{"type": "8-K", "sequence": "1", "filename": "a13-12933_48k.htm", "description": "8-K", "secsgml_size_bytes": 34051}]
{"company-data": {"conformed-name": "AFFILIATED MANAGERS GROUP INC", "cik": "0001004434", "assigned-sic": "6282", "irs-number": "043218510", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "8-K", "act": "34", "file-number": "001-13459", "film-number": "131014252"}, "business-address": {"street1": "600 HALE STREET", "street2": "P.O. BOX 1000", "city": "PRIDES CROSSING", "state": "MA", "zip": "01965", "phone": "6177473300"}, "mail-address": {"street1": "600 HALE STREET", "street2": "P.O. BOX 1000", "city": "PRIDES CROSSING", "state": "MA", "zip": "01965"}}
UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, DC 20549
FORM 8-K
CURRENT REPORT PURSUANT
TO SECTION 13 OR 15(D) OF THE
SECURITIES EXCHANGE ACT OF 1934
Date of report (Date of earliest event reported):
August 6, 2013
Affiliated Managers Group, Inc.
(Exact Name of Registrant as Specified in Its Charter)
Delaware
(State or Other Jurisdiction of Incorporation)
001-13459
04-3218510
(Commission File Number)
(IRS Employer Identification No.)
600 Hale Street
P.O. Box 1000
Prides Crossing, Massachusetts
01965
(Address of Principal Executive   Offices)
(Zip Code)
(617) 747-3300
(Registrant's Telephone Number, Including Area Code)
N/A
(Former Name or Former Address, if Changed Since Last Report)
Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (
see
General Instruction A.2. below):
o
Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)
o
Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)
o
Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))
o
Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))
ITEM 8.01
Other Events.
On August 6, 2013, Affiliated Managers Group, Inc. (the "Company") filed a registration statement and prospectus supplement following the expiration of its existing registration statement.  The prospectus supplement effectively replaces that filed in August 2012, which provided for the sale of up to $400 million in shares of the Company's common stock.  The Company sold $147.2 million under that supplement pursuant to forward sale arrangements (which have not yet been settled), with $252.8 million of sales capacity remaining. The Company has no current intention to sell additional shares of common stock at this time.
In connection with this prospectus supplement, the Company has entered into initial forward sale agreements and distribution agency agreements with each of Merrill Lynch, Pierce, Fenner & Smith Incorporated, Deutsche Bank Securities Inc., Citigroup Global Markets Inc., Mitsubishi UFJ Securities (USA), Inc., RBC Capital Markets, LLC, Scotia Capital (USA) Inc. and Wells Fargo Securities, LLC (or an affiliate of the same).  The forms of such agreements are attached as Exhibits 10.1 and 10.2 hereto.  In addition, Ropes & Gray LLP issued an opinion regarding the validity of shares to be issued pursuant to forward sale agreements, which is attached as Exhibit 5.1 hereto.
ITEM 9.01
Financial Statements and Exhibits.
(d)
Exhibits.
Exhibit No.
Description
5.1
Opinion of Ropes & Gray LLP as to   the validity of the shares to be issued pursuant to each of the Confirmation   Letter Agreements dated August 6, 2013 and any subsequent related   Confirmation Letter Agreements.
10.1
Form of Confirmation Letter Agreement,   dated as of August 6, 2013.
10.2
Form of Distribution Agency Agreement,   dated as of August 6, 2013.
2
SIGNATURES
Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.
AFFILIATED MANAGERS GROUP, INC.
Date: August 6, 2013
By:
/s/ John Kingston, III
Name:
John Kingston, III
Title:
Vice Chairman,
General Counsel and Secretary
3
EXHIBIT INDEX
Exhibit No.
Description
5.1
Opinion of Ropes & Gray LLP as to   the validity of the shares to be issued pursuant to each of the Confirmation   Letter Agreements dated August 6, 2013 and any subsequent related   Confirmation Letter Agreements.
10.1
Form of Confirmation Letter Agreement,   dated as of August 6, 2013.
10.2
Form of Distribution Agency Agreement,   dated as of August 6, 2013.
4