ICICI Bank chief Chanda Kochhar and Axis Bank chief Shikha Sharma have been summoned by the Serious Fraud Investigation Office (SFIO) in connection with the over Rs 13,000-crore PNB scam. ICICI Bank had led a consortium of 31 banks which had lent Mehul Choksi's Gitanjali Gems Rs 1,000 crore. Choksi is Nirav Modi's uncle and partner. Also read: Rahul Gandhi questions PM Modi's silence, says 'ek Nirav Modi Hai, dusra Modi nirav hai' PTI reported that the SFIO has asked the heads of all 31 banks to come in for questioning. Kochhar, Sharma and the other bank chiefs are expected to be questioned at the SFIO's headquarters in Mumbai. Kochar and Sharma will be questioned about the loans their banks made to Modi and Choksi but, news reports said, they are not being seen as suspects in the scam. The PNB scam is being investigated by a slew of agencies including the CBI, the Enforcement Directorate and the SFIO. The scam was first reported from a Mumbai branch of the Punjab National Bank. It is alleged that PNB officials colluded with Modi and others to issue them Letters of Understanding (LoUs), basically bank guarantees. It was on those LoUs that Modi and Choksi got their bank loans.