Hong Kong protests 'worrying,' says WPP CEO

WPP CEO: Strong bull on China
WPP CEO: Strong bull on China   

The growing pro-democracy protests in Hong Kong are "worrying," Sir Martin Sorrell, top executive at the world's largest advertising conglomerate, told CNBC on Monday.

"Obviously the demonstrations are troubling and I think is a cause for concern," Sorrell, CEO of WPP, told "Squawk on the Street." "We haven't seen demonstrations of that nature for a significant period of time."

A protester throws an umbrella at riot police as fellow demonstrators blocked the main street to the financial district outside government headquarters in Hong Kong Sept. 29, 2014.
Tyrone Siu | Reuters
A protester throws an umbrella at riot police as fellow demonstrators blocked the main street to the financial district outside government headquarters in Hong Kong Sept. 29, 2014.

The protests, which picked up momentum over the weekend, only intensified on Monday. Riot police fired rounds of tear gas and demonstrators continued to block roads on Monday, leading schools and banks to close.

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"The Hong Kong electorate are calling for a greater freedom for the selection of candidates, not having a slate of candidates determined by Beijing," Sorrell said. "I think it is worrying from the point of view of China as a whole."

After all, the protests could be a tipping point for the city, which had been a British colony for 99 years until its lease expired in 1997. Hong Kong's transfer from the United Kingdom back to China didn't happen instantly, though. Instead, China agreed to wait 50 years to complete the shift.

In turn, it remains unclear whether Hong Kong will remain a special administrative region or become fully absorbed by the mainland when the transfer is finally completed in 2047.

Martin Sorrell
Chris Ratcliffe | Bloomberg | Getty Images
Martin Sorrell

A lot hinges on Hong Kong, too, as the densely populated city is booming with business, especially in the areas of finance.

"China is our third-largest market and Hong Kong is a major area for us, as well," Sorrell said, adding his advertising firm currently employs 16,000 across 80 cities in China, generating roughly $1.5 billion in annual revenue from the country.

In turn, Sorrell said much is riding on how things shake out in Hong Kong.

"I would say it is troubling. It is concerning," he said. "But we'll have to see how things develop."

—CNBC's Evelyn Cheng contributed to this report.