The Hong Kong Stock Exchange on Thursday completed its takeover of the London Metal Exchange, the pair said in a statement.
"Hong Kong Exchanges and Clearing Limited (HKEx) and LME Holdings Limited (LME Holdings), the parent company of The London Metal Exchange Limited (LME), are pleased to announce that the acquisition of the entire issued ordinary share capital of LME Holdings by HKEx has completed today," they said.
HKEx, the holding company of Hong Kong's bourse, agreed to buy the 135-year-old LME in June, when it was valued at £1.39 billion (US$2.15 billion, 1.77 billion euros).
The following month, LME shareholders voted overwhelmingly in favour of the takeover.
"We are delighted that, as of today, the LME is formally part of the HKEx group," said HKEx Chief Executive Charles Li on Thursday.
"We are confident that this partnership will deliver enormous benefits over time as we leverage our relationships and knowledge to build on LME's strong global position."
The Hong Kong Stock Exchange said late last month that it would sell $1 billion in new shares to fund the takeover, which has already received the green light from British regulators.
"The LME will remain the world's foremost base metals exchange thanks to HKEx's position in Asia, its infrastructure and resources," added LME boss Martin Abbott in the statement.
"We begin a new chapter today but the LME is more secure than at any point in its 135-year history."
HKEx has said its purchase of the LME -- the world's largest exchange trading non-ferrous metals, including aluminium and copper -- will strengthen its role as a bridge between China and international markets.
"The transaction brings together the leading operator of exchanges and clearing houses in Asia, with the world's leading non-ferrous base metals trading venue," the two groups added on Thursday.