The COO of Las Vegas Sands’ Macau subsidiary, David Sisk, has resigned.

The departure of Sisk, a veteran of the Las Vegas casino industry, comes after a tenure of three years at the Macau gambling resort operator controlled by billionaire Sheldon Adelson.

Sisk “has resigned and is no longer with the company,” the Las Vegas Sands unit said in an e-mailed statement, without providing a reason for his departure.

Sands China has more than doubled its revenue over the last four years, while losing some top executives along the way. Former CEO Steven Jacobs sued Sands in 2010, claiming wrongful dismissal, after he was fired.

Sisk joined Sands in 2010 as chief casino officer and in his most recent role was second to CEO Edward Tracy. Before coming to Sands China, he had held senior roles at Las Vegas casinos including Wynn Resorts.

Sands has said it plans to invest another $2.8bn in the former Portuguese colony to build its fifth resort, to be named Parisian, to attract middle-class gamblers from China.