The register
The register lists SThree in Glasgow as a licensed sponsor on Global Business Mobility: Senior or Specialist Worker and Skilled Worker, 2 routes in all, and has done since at least 2026. Rating on the current register: Worker (A rating).
Companies House lists it as Sthree PLC, number 03805979, incorporated 1999: 27 years of filings behind the name. The registered office is at Level 16 8 Bishopsgate, London, EC2N 4BQ, EC2N 4BQ. Its filed activity puts it in professional and technical services. It has traded under other names before, including Sthree Limited, Solutions in Staffing and Software Limited.
Holding a licence is the expensive, slow part done. For SThree the question each time is only whether the role and the pay fit the current rules, and that is checked per vacancy.