A billboard advertising the Upper in Shanghai, March 1, 2016.[Photo/IC]

The Upper, an apartment complex located within the Shanghai Inner Ring and developed by Shanghai Ruihong Xincheng Co, thrilled the property sector at the beginning of this year.

On Feb 21, the developer sold all 352 units, priced at 80,000 yuan per square meter, in just five hours, raking in 3.6 billion yuan ($549.4 million).