The liquidity deficit in the banking system is likely to widen this week on the back of outflows on account of GST payments, experts said. This will lead to marginal uptick in yields on short-term debt instruments such as T-bills, commercial papers and CDs, among others. Liquidity in the banking system as on March 18 was pegged at a deficit of around Rs 72,918.47 crore, as per RBI data.