Exhibit 21

Subsidiaries of the Parent Company

As of December 31, 2017

The following bank subsidiaries are national banks and are organized under the laws of the United States:

Associated Bank, National Association

Associated Trust Company, National Association

The following nonbank subsidiary is organized under the laws of the State of Nevada:

Associated Investment Corp.

The following nonbank subsidiaries are organized under the laws of the State of Wisconsin:

Associated Community Development, LLC

Associated Financial Group, LLC

Associated Investment Services, Inc.

Associated MN Commercial RE, LLC

Associated Wisconsin Real Estate Corp.

Kellogg Asset Management, LLC

ACD Germania, LLC

Milwaukee Center Management, LLC