86. Business Systems International

Revenue: £53.3m (-2.2%)

Staff: N/A

After an over 30 per cent revenue dip in calendar 2021, this London IT shop's most recent reporting period, to March 2023, saw another contraction, this time less severe.

Even so, the business stated that its financial position 'remains strong' with the majority of its business again being generated by hedge funds and systematic trading firms.