Our Team


Tammy Siegl

Development Coordinator

Office: Madison, WI

Focus: Assisting Developers with technical and administrative support for a variety of real estate activities from due diligence and feasibility all the way through the closing process.  In addition,  Tammy oversees the operations of the Madison office.

Experience: Tammy earned her Bachelor’s degree from the University of Wisconsin-Madison in Political Science. Before joining Commonwealth Development Corporation, Tammy was with Mirus Partners, Inc. since its formation in 2013.  She assisted with property acquisitions, coordinated preparation of financing proposals, and oversaw the office operations.  Prior to the formation of Mirus Partners, Tammy worked for Silverstone Partners, a related party, since 2010 in a similar role.

Impressive Facts: Tammy is a World Class Drum and Bugle Corps alumni and tries to attend as many corps shows during the summer that she can.  She has been known to get her flag & rifle out on occasion and practice spinning in the backyard.

Fun Stuff: Tammy and her husband spend quite a bit of time attending UW-Madison sporting events as both of their kids attend the UW, where her daughter is also a cheerleader.  She enjoys the outdoors, traveling and spending time with friends.

Commonwealth is creating opportunities through affordable housing to help people be successful in their communities.


Commonwealth Companies merges with Middleton-based developer

The Commonwealth Companies set its eyes on growth as it merged with Mirus Partners, Inc. Thursday. The merger creates a…
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Preserving for Affordability

The Commonwealth Companies is a vertically integrated real estate developer and property manager creating affordable housing throughout the country. The…
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Commonwealth has been extremely professional and courteous to the staff and the residents still living in our facility. They exceeded our expectations during the construction project as well as during the renovation of a 1923 school. Both projects have turned out to be beautiful and successful for our community.

Nancy McKenzie, Executive Director , Rhinelander Housing Authority