Top banks suspend accounts of major Bitcoin exchanges in India.

Top lenders including State Bank of India, Axis Bank, HDFC Bank, ICICI Bank and Yes Bank have suspended some accounts of major Bitcoin exchanges in India, suspecting dubious transactions, three people aware of the development said.

The banks have also sought additional collateral from the promoters of these exchanges on their borrowings and have capped cash withdrawals from the few accounts that are still operational.

"Since last month, banks have been asking for additional collateral with 1:1ratio," a person with knowledge of the matter said.

The banks are scrutinising current accounts held by top Bitcoin exchanges, a second person said. Action has been initiated against the top 10 Bitcoin exchanges including Zebpay, Unocoin, CoinSecure and BtcxIndia, said four people aware of the matter.

The banks have not contacted the company or the promoters regarding the actions you have mentioned," said Sathvik Vishwanath, promoter of Unocoin.

Emailed queries to Zebpay, Coin-Secure and BtcxIndia did not elicit any response. SBI, Axis Bank, HDFC Bank, ICICI Bank and Yes Bank did not respond to emails seeking comment.

Bitcoins are a digital currency that can be used to buy products and services without any intermediary. People also buy Bitcoins, which has been banned in some countries, as an investment.