When Hong Kong released its economic data on Wednesday, a milestone of sorts was reached in China's economically powerful 11-city Greater Bay Area.
The figures put Hong Kong's GDP for 2017 at 2.66 trillion Hong Kong dollars, the equivalent of 2.15 trillion yuan, which meant that on the day's exchange rate, the special administrative region had been surpassed by neighboring Shenzhen for the first time on some measurements.
Shenzhen's GDP was 2.24 trillion yuan, putting it at the top of the Guangdong-Hong Kong-Macao Greater Bay Area that the government has earmarked for an integrated economic and business hub.
Some say, however, that GDP figures should be converted by the annual average exchange rate, not that of a single day. By that measurement, Hong Kong's 2017 GDP is 2.3 trillion yuan, still higher than that of Shenzhen, a tech-heavy city.
Professor Zhang Guangnan of the Institute of Guangdong, Hong Kong, and Macao Development Studies at Sun Yat-Sen University said there is a lot more to focus on than just GDP rankings.
"The ranking of a single indicator is not that important," he said. "GDP represents economic aggregate and its growth, not social development and maturity.
"It's more important for us to focus on a city's sustainable development of multiple aspects, including economy, society, environmental resources, to enhance cooperation between cities, therefore making a stronger cluster."
Zhang also pointed out that Shenzhen has advantages in innovation and talent and its local industrial chain, while Hong Kong keeps its position as a free port and reputation for professional services in finance, trade, and shipping.
He said the Guangdong-Hong Kong-Macao Greater Bay Area provides unprecedented opportunities for regional cooperation, not only for Shenzhen and Hong Kong, but for all the cities in the area.