Law firm TLT has reported a 7% rise in turnover to £87.6m for 2018/19.
The company recently expanded in Northern Ireland following a relocation to River House on Belfast's High Street.
TLT employs around 1,000 people across the UK, with 60 based in Belfast. The firm said the new River House space has capacity for over 100 people, which it hopes to reach with plans for further investment.
The company said the 2019 performance meant its turnover had doubled since 2012.
NI partner and location head Katharine Kimber said: "We are winning market share in a competitive environment with a clear, consistent and client-led approach.
"We have been involved in some major developments in Belfast in the last year and continue to build expertise in our specialist sectors in recognition of client need."
She added: "We have extended our service offering for clients in Belfast through our recent hires in corporate, dispute resolution, banking, real estate, insolvency and employment."