New Delhi: The fraud case at Punjab National Bank (PNB) underscores the urgent need for reforms at public sector banks, said rating agency S&P. It said that the fraud comes as the sector continues to reel from soaring non-performing assets (NPAs) in an extended downcycle. However, tighter regulatory standards combined with generous capital injections should strengthen balance sheets, according to an article published on Monday by S&P Global Ratings and titled, "Darkest Before The Dawn: Fraud Case May Hasten Reform For India's Banks." "We expect further losses at India's public sector banks but the bulk of previously unacknowledged stressed assets have already been recognised," said Deepali Seth-Chhabria, analyst at S&P Global Ratings.