This year was already a fertile one for dealmakers in Hong Kong leading into Thursday. Then came HSBC Holdings Plc with its proposed $14 billion buyout of Hang Seng Bank Ltd. to really put a rocket under things.

HSBC’s offer — buy the 37% of Hang Seng Bank it doesn’t own already — pushes this year’s potential volume of deals such as mergers and acquisitions involving companies in Hong Kong to $74 billion, a roughly 40% jump from the same period a year ago, data compiled by Bloomberg show.