Shanghai has more than 1000 formal bus lines (including city center and suburban lines), served by more than 10 bus companies. In the past, Bashi, Dazhong, Guanzhong and Qiangsheng were the four largest; around 2009 they merged to become Bashi Group Companies, including Bashi No.1-6 Bus Passenger Service Companies, Bashi Tram, Bashi Xinxin and Chongming Company, Baoshan Company and Jinshan Company. Each Suburban district also renewed with one company serving each district. Around 2015, Bashi No.1 Passenger Service and Bashi Tram merged to be Bashi No.1 Company, Bashi No.2 Passenger Service became Bashi No.2 Company, Bashi No.3, No.4 Passenger Service merged to be Bashi No.3 Company, Bashi No.6 Passenger Service became Bashi No.4 Company, and Bashi No.5 Passenger Service and Baoshan Company became Bashi No.5 Company.