We are a Chicago-based private equity firm that makes control investments in middle market companies. Since 1994, we have utilized our deep industry knowledge and extensive executive relationships to create value with our portfolio companies.


About Us

We typically invest in middle market companies with enterprise values ranging between $30 million and $500 million. Collectively, we have over 50 years of experience in private equity and have invested more than $3 billion in equity capital in 200+ transactions.

We target three business sectors:

  • Infrastructure Services
  • Niche Manufacturing
  • Education Services

Our goal is to invest in companies that can benefit from our extensive strategic, financial and operational experience.

We create long-term partnerships with our management teams that have lasted well beyond the life of our investments. These relationships have been built on a foundation of experience, trust, transparency and integrity.

Our Investment Strategy

We believe maximizing value means building our companies as if we are going to own them forever.

Our Portfolio

Our unique approach focuses on aligning our core values and strategic approach with our partners to build sustainable, long-term value and market leadership.


Active Investments

Past Investments


Our team has broad investment and management experience coupled with specific industry expertise and a passion for what we do.

Recent News

Contact Us

We'd love to hear from you.

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Willis Stein & Partners
1033 Skokie Blvd Ste 360
Northbrook, IL 60062-4137

Phone: 312-422-2400
Fax: 312-422-2424