The latest division in Hong Kong isn't driven by posters and protests — it's driven by consumers' wallets as people vote with their money.

The city's economy shrank in the second and third quarter of 2019, marking a technical recession and the first time in a decade its economy weakened for two consecutive quarters. The government forecasts the economy will contract by 1.3% in 2019 as the Asian financial hub braces for its first budget deficit in 15 years.

While most businesses want to stay out of politics, many have faced declining sales — partially as a result of a 40% decline in visitor numbers in the second half of 2019.

Yet, phone apps have popped up showing maps of businesses believed to be supporting the protests, as well as those that are not. The grass roots movement distinguishes businesses as yellow if they are vocal about the demonstrations, or assumed to be promoting the pro-democracy protests. Blue, on the other hand, is used for businesses perceived to be either against the protesters and/or are backing the government and police.

One Instagram account, for instance, has amassed more than 190,000 followers since its launch in September and shows and promotes, so-called "yellow businesses" that support the protests.

CNBC visited several businesses, including Lung Moon Restaurant in Hong Kong's Causeway Bay district, which has a sign on its window declaring: Stand with Hong Kong.