PB Fintech shares plunged 7 percent to hit a 52-week low on Monday after its September quarter earnings drew mixed reactions from brokerages, with some analysts flagging higher operating costs while others remained positive on the company's growth prospects. The stock fell to Rs 928.20 per share on the NSE, marking a decline of 7 percent from its previous close of Rs 1,000.10. HSBC said the company's second-quarter earnings missed estimates, mainly due to elevated operating costs.