(Adds more details, background) SHANGHAI, Aug 20 (Reuters) - China Telecom Corp opened 5.7% higher on its first day of trading in Shanghai, after raising $7.3 billion in the world’s biggest public share offering so far this year. After having opened at 4.79 yuan in Shanghai, compared with its offer price of 4.53 yuan, shares of the telecom giant pared some gains later and struggled to stay above the offer price amid weakness in broader market. The blue-chip CSI300 index lost more than 1%. U.S.-blacklisted China Telecom, which was kicked off the U.S. stock exchange in May, had raised 47.1 billion yuan ($7.3 billion) in Shanghai as it broadened its funding channel at home. The debut follows a growing number of U.S.-listed Chinese companies that are selling shares publicly in Hong Kong or mainland China amid Sino-U.S. tensions. Meanwhile, Hong Kong-listed shares of the company slumped more than 5% on Friday morning, trading at roughly half the price of its Shanghai counterparts. $1 = 7.7910 Hong Kong dollars Reporting by SHANGHAI NEWSROOM; Editing by Himani Sarkar and Uttaresh.V Our Standards: The Thomson Reuters Trust Principles.