LONDON--The Hong Kong stock exchange says it has started talks to buy the London Stock Exchange that would value the British company at 29.6 billion pounds ($36.6 billion or 3.9 trillion yen).

The Hong Kong Exchanges and Clearing Ltd. said Wednesday that a deal would provide the London Stock Exchange with a key opening to Asian markets and underpin the British capital's role as a financial hub.

The offer comes at a time of heightened uncertainty for London and British companies because of Brexit, which threatens to create barriers to trade for the country. A weakened pound has also made U.K. companies cheaper takeover targets.

The Hong Kong exchange is required to make a binding offer by Oct. 9.