(Bloomberg) -- Shares of India’s second-largest cement maker have been put on a short-term watchlist after they surged more than 40% following billionaire Gautam Adani’s acquisition of the company in May.

Ambuja Cements Ltd. was added to the Additional Surveillance Mechanism, which the bourse uses to “alert and advice investors to be extra cautious while dealing in these securities,” according to the National Stock Exchange of India Ltd.’s website on Sept. 21. Adani spent $6.5 billion to buy a controlling stake in Ambuja and ACC Ltd. from Swiss firm Holcim Ltd.

Stocks on the list tend to witness selling pressure as they undergo extra scrutiny for up to 15 trading sessions and face higher margin rates. In one recent example, shares of Coffee Day Enterprises Ltd., which operates a cafe chain, slid more than 10% over three days after being put on the list Sept. 14.

Ambuja Cements lost 7% in the previous two sessions before rising on Friday.

“It is rare for a big stock such as Ambuja Cements to enter the ASM framework,” said Suniil Pachisia, head of institutional equity desk with Pratibhuti Vinihit Ltd. “Besides preferential allotment there is no other reason for this run-up and it is a good step to counter the volatility.”

Adani Group has encumbered about $13 billion of its stake in the two cement firms under a non-disposal undertaking with the lenders, reflecting the world’s second-richest person’s hunger for capital as his ports-to-power conglomerate expands rapidly.

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