(Yicai Global) March 10 -- As Costco Wholesale’s second members-only store in Shanghai opened its doors to the public today, the US big-box retailer capped shopper numbers at 20,000, fearing that too many would show up, causing chaos on its first day of trial operation.

A long line had already formed at 8 a.m. when an Yicai Global reporter reached the new store in the city’s Pudong district.

With the success of Costco and Sam’s Club, another US-based membership-only retail warehouse chain, the membership-only model is becoming a must-have strategy for hypermarket operators in China. Costco aims to open four new shops in the country this year and Sam’s Club plans to open outlets in city centers.

Carrefour China, the supermarket chain majority owned by Chinese retail giant Suning.Com, intends to convert half of its 200 outlets into membership-only stores within three years. RT-Mart recently said it will open its own membership-only shops. Hema Fresh, the grocery chain of Alibaba Group Holding, has launched several Hema X members-only outlets in Beijing, Shanghai, Nanjing, and Suzhou.

A banner on the side of Costco’s new Shanghai store announces its opening on March 10.

Customers line up before the doors open.

During the trial operation, Costco is offering a limited number of BMW i3 and iX3 electric models at between CNY200,000 and CNY300,000 (USD28,710 and USD43,060), a discount of 30 percent to 43 percent.

Customers flock to the store’s meat section.

Editors: Tang Shihua, Futura Costaglione