The firm said pre-tax profit reached £685 million in 2020, from £651 million a year earlier, as revenue grew 3% to £2.1 billion.
In January the company completed its approximately £20 billion acquisition of data giant Refinitiv, a move which LSEG believes will be “transformational”.
LSEG chief executive David Schwimmer said: “The Covid-19 pandemic and broader geo-political events presented unprecedented challenges in 2020.
“Despite this environment, and with the vast majority of employees working remotely across our global locations, LSEG has delivered for its customers and provided a strong financial performance, demonstrating strong operational resilience.
“We continue to innovate and work in partnership with our customers to develop our services, in areas such as reference rate reform and sustainable investment.
“Completion of the acquisition of Refinitiv in early 2021 marked an important milestone in LSEG’s history.”