Contemporary Amperex Technology Co Ltd is trading at a record premium in Hong Kong over its Chinese mainland-listed stock, likely an indication of global investors’ strong interest in the battery giant.

CATL’s shares have surged 46 percent in Hong Kong following a May debut. They are now 30 percent more expensive than those trading in Shenzhen after adjusting for currency differences. That’s a rare markup, as the majority of the roughly 150 dual-listed companies suffer a discount in the city, partly due to a difference in taxes for mainland investors.

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While a boom in Hong Kong listings this year has seen a few stocks trade at a premium over mainland peers, such high double-digit differences have been rare. One extreme case in the past was Anhui Conch Cement Co — whose Hong Kong stock commanded a 68 percent premium over its Shanghai peer in 2014 — but that anomaly quickly dissipated once the Shanghai stock connect opened later that year and made it easier for global funds to access the mainland market.

Analysts at JPMorgan Chase & Co. attribute CATL’s high premium to low liquidity due to a post-listing lock-up, a short squeeze as a majority of the outstanding shares have been borrowed, and the stock’s popularity among global investors. However, they caution that a pullback may follow the sharp rally.