New Delhi, April 23 -- In an open letter to Prime Minister Narendra Modi, global brokerage firm Bernstein on Thursday called for a more coordinated push to formalize India's economy, restrict cash-driven informal activity and boost digital transactions. The firm also suggested ways to broaden the country's tax base, saying that India has become more of a user than a driver of technological advancement.

Bernstein said informal transactions and heavy cash use persist despite rapid growth in digital payments, limiting transparency. "Informal transactions and cash usage persist despite progress in digital payments. Addressing this requires more than incremental measures," the letter said, which was seen by LiveMint.

The brokerage firm argue...