Jardine Matheson said it would spend some £166.27m on buying the extra stake in JLT, which would bring its shareholding in the insurance broker up to 40.35 per cent. It is offering 765 pence per share to acquire the new JLT stake.
The 765 pence-per-share offer represents a premium of around 24 per cent to Jardine Lloyd Thompson's closing share price of 619 pence on 24 September.
"JLT is a core strategic investment of the Jardine Matheson Group and the partial offer reinforces our commitment to the stability, independence and long-term growth of JLT," Jardine Matheson managing director Anthony Nightingale said in a statement.
In July, Jardine Lloyd Thompson posted an 8 percent rise in half-year profits, helped by strong growth in Australia and Asia.
Jardine Matheson, which was founded as a trading company in China in 1832, has business interests ranging from construction to transport and financial services, with a primary focus on Asia.