New Delhi, Oct. 28 -- Jio Platforms made a strong stock-market debut on Wednesday, opening 21% above its issue price even as the Sensex fell more than 1%. The key test now is whether the issuer of India's largest initial public offering (IPO) to date can hold that premium through the close, unlike India's five largest previous debuts. A Mint analysis shows that none of those five predecessors gained more than 2% on day one, and three ended below their offer prices.

Jio's Rs.30,213-crore IPO was subscribed 22 times overall, stronger than any of those five predecessors, with retail investors bidding for 2.7 times their allocation. Sustained buying in the secondary market will determine whether it retains its early gains.

The opening premi...