The move comes ahead of the results of an unofficial referendum, which has been branded illegal by the former British territory and by Beijing, on proposed electoral reforms related to a vote in 2017 to elect Hong Kong's next leader.
Occupy Central with Love and Peace, the organisers of the referendum, have threatened to lock down the Central area of Hong Kong, home to some of Asia's biggest companies and banks, as part of its campaign to demand greater democracy in elections for the city's leader, or chief executive, in 2017.
Chinese authorities are keen to ensure that only pro-Beijing candidates make it on to the ballot. Democracy activists want the nomination process to be open to everyone.
The ads were signed by Ernst & Young [ERNY.UL], KPMG [KPMG.UL], Deloitte Kwan Wong Tan & Fong [DLTE.UL], the company's Hong Kong unit, and PricewaterhouseCoopers [PWC.UL].
"It means China is exerting all possible influence over all groups they can influence," said Benny Tai, associate professor of law at the University of Hong Kong and one of the organisers of the referendum.
This is not the first time Business has decided that democracy might be a bit inconvenient in this region. China is also not happy about the British Deputy minster meeting the protesters.