Zijin Mining Group Co’s shares listed in the Hong Kong Special Administrative Region are trading near a record premium over those in the Chinese mainland, as foreign investors rush to buy the stock of a company enjoying a boom period for gold and copper.

The company’s HKSAR shares have jumped around 115 percent so far this year, eclipsing the 86 percent rise in its mainland-listed stock, according to Bloomberg-compiled data. That has erased a discount on the offshore shares that has held for years, a sign that Zijin Mining’s rising global footprint has put it into the spotlight for investors.

The recent rally pushed Zijin Mining’s market value above $100 billion this week, helping it join the big leagues of metal miners like Rio Tinto and BHP Group Ltd. Analysts think there is still room for the surge to run: Zijin Mining’s shares in both markets have unanimous buy recommendations among sell-side analysts tracked by Bloomberg.

Zijin Gold International Co, which owns the company’s gold mines outside of the mainland, is set to raise HK$25 billion ($3.2 billion) from an initial public offering in the HKSAR. It pushed back the listing to next week after the HKSAR was hit by a super typhoon, disrupting business in the city.

“Given that sentiment on gold and copper prices remains positive, there should still be more upside for Zijin,” said Jack Shang, an analyst at Citigroup Inc. The gold unit IPO bodes well for Zijin “since an offshore listing gives the company more flexibility to acquire overseas assets and expand production”, he added.

The premium between the HKSAR and onshore shares hit a record of 6.6 percent earlier this week, according to Bloomberg-compiled data.