For investors lucky enough to land shares in Jio Platforms Ltd.’s $3.1 billion IPO, trading on the unofficial market is fuelling hopes of a big debut pop. Billionaire Mukesh Ambani’s digital and telecommunications giant has attracted stellar demand across investor categories ahead of its 28 October market debut. Investors who got their allocations on Tuesday are now closely watching Jio’s grey-market pricing for clues about how the first day might unfold.