36. Six Degrees

Key points

Revenue: £101.6m (+25%)

EBITDA margin: 18%

Staff: 539

Constructed from 20 acquisitions over seven years, private equity-backed Six Degrees is striving to be the UK's top converged managed services provider for mid-market and large firms. Its ultimate parent company, CB-SDG Topco, posted revenues of £101.6m in its year ending 31 March 2017, up from £61.1m in the previous nine-month period, as its acquisitions of Carrenza and Insite boosted its top line. Although net losses widened to £44.9m on the back of hefty amortisation and interest charges, EBITDA rose to £18.3m.