Star Equity Holdings, Inc. is a diversified holding company. Its segments include Building Solutions, Business Services, Energy Services, and Investments. Its Building Solutions segment provides service for residential and commercial construction projects by manufacturing modular housing units and other products, supplying general contractors with building materials and providing glue-laminated timber products to distributors and end users. Its Business Services segment delivers recruitment process outsourcing services consisting of recruitment and contracting solutions tailored to the individual needs of mid-to-large multinational companies. Its Energy Services segment consists of Alliance Drilling Tools, Inc., a Wyoming and Texas-based provider of drilling tools and services to the energy industry. Its Investments segment holds and manages certain of its corporate-owned real estate, including a manufacturing facility in Maine and a manufacturing facility in Wisconsin.