All modes of retail digital payments registered growth in transaction volumes in December, with the Unified Payments Interface (UPI) channel continuing to grow the fastest, representative data released by the Reserve Bank of India (RBI) showed. The volume of UPI transactions grew 39% month-on-month (m-o-m) to 145.5 million and the value rose 36% to Rs 13,144 crore. There was, however, a decline in average ticket size of a UPI transaction to Rs 903 from Rs 919 in November. Next in line was Immediate Payment System (IMPS), which saw volume growth of 9.5% m-o-m to 98 million, while the value grew 11% to Rs 87,106 crore. Wallets and other prepaid payment instruments (PPIs) issued by eight entities clocked Rs 3,505 crore, up 12% from November, on 99 million transactions, up 9% from the previous month. Based on this, the average ticket size of a wallet transaction works out to about Rs 354, up from Rs 345 in November. The average value of a UPI transaction has typically been higher than that of a wallet transaction because use of the former channel has so far been limited to peer-to-peer payments, while wallets are more commonly used to make small-value payments to merchants. The gap, however, is closing as UPI adoption increases. Among other modes of retail payments, debit and credit card transactions at point-of-sale (PoS) terminals rose 6% m-o-m in volume terms to 257 million. The aggregate value of card transactions rose 7.5% from the previous month to Rs 51,591 crore. This data is based on card transactions sourced from four banks and the final figure for the entire system is likely to be much higher. The Unstructured Supplementary Service Data (USSD) channel saw volumes remaining unchanged at 0.18 million. However, the value of transactions increased 4% from their November level to Rs 30 crore.