Grey market signals solid listing gains in GR Infra, Clean Science & Zomato SECTIONS Share Synopsis The grey market premia of Zomato and Tatva Chintan Pharma Chem (TCPC) -- whose IPO is still one -- also remain sturdy, signalling solid buying interest in the primary market. iStock Listing candidates GR Infra and Clean Science & Technology are trading at a premium of Rs 560 and 610, respectively, in the unofficial market. Related New Delhi: GR Infraprojects and Clean Science & Technology are set for a strong debut on Monday, as grey market premia suggested solid interest in the stocks after a robust response from investors during the book building process.