(Reuters) - Chinese conglomerate Fosun International will buy the remaining stake in Shanghai Henlius Biotech that it does not already own in a deal that values the Hong Kong-listed drugmaker at HK$13.37 billion ($1.71 billion), the companies said on Monday.

Fosun International, through its unit Shanghai Fosun Pharmaceutical, is offering HK$24.60 per Henlius share, which reflects a premium of 30.6% to the target's last close.

Henlius shares last traded on May 22, having closed at HK$18.84, after the firm issued a trading halt pending an announcement on takeovers and mergers.

Fosun Pharma is also the controlling shareholder of Henlius Biotech and through its other affiliates, owns a total of 65.23% in the Hong Kong listed drugmaker.

Fosun International is one of the country's biggest listed conglomerates and includes a diverse set of companies, carrying out operations from retail to real-estate.

($1 = 7.8075 Hong Kong dollars)

(Reporting by Rishav Chatterjee in Bengaluru; Editing by Shounak Dasgupta and Shailesh Kuber)