A spokeswoman for Lion Capital told FoodManufacture.co.uk: “We are not commenting on Weetabix at present.”
The state-backed Bright Group has been in negotiation with Lion Capital for weeks, according to press reports.
Bright has shown an appetite for European firms for some time. It lost out to General Mills for a stake in French yogurt maker Yoplait last year.
Weetabix produces about 70M high-fibre cereal biscuits each week, which generates sales of £423M. Other brands include Alpen, Oatibix and Ready Brek.
The firm won the Manufacturing Company of the Year Award and the Ambient Company of the Year accolade at Food Manufacture's Food Manufacturing Excellence Awards last year.