Quad-C Management Inc., a Virginia-based middle market private equity firm, invested in IT staffing provider S.i. Systems.

The company’s founder and CEO, Derek Bullen, maintains a “significant” ownership position, according to the firms, and continues to lead S.i. Systems as CEO following the Quad-C investment.

S.i. Systems, headquartered in Calgary, Alberta, ranks seventh on Staffing Industry Analysts’ list of largest staffing firms in Canada. It operates 14 offices across Canada and provides IT staffing for financial services, energy, public sector, telco/media/technology, and consumer services.

Bullen said the investment accelerates S.i. Systems’ ability to grow organically and via acquisitions.

“This is a tremendous opportunity to grow personally and professionally as we continue the buildout of S.i. Systems” he said. “Quad-C has proven expertise in professional staffing and brings a new level of strategic and operational insight to the company.”

Quad-C Management last year sold staffing provider Vaco to private equity firm Olympus Partners.