Three South Korean banks with crypto exchange partnerships have reportedly made $14.71 million in transaction fees in the second quarter of 2021.

According to The Korea Herald, Shinban Bank, K bank and NH Nonghyup Bank announced a total revenue of 16.9 billion South Korean won in Q2.

The “big four” crypto exchanges in South Korea — Upbit, Bithumb, Coinone and Korbit — have partnered with the banks for sourcing users’ real-name accounts.

Based on the data collected by Yun Chang-hyun, the second quarter performance exceeded the first quarter’s approximately $6.8-million (7 billion won) mark, more than doubling transactions despite ongoing market fluctuations.

The data shows that K bank’s partnership with Upbit resulted in the biggest share of $10.4 million (12 billion won), over 71% of the total revenue. In the first quarter, the bank made 5.2 billion won through the crypto exchange partnership.

NH Nonghyup’s two-way partnership with Bithumb and Coinone wasn’t as impressive as K bank’s revenue. With Bithumb, the bank reported earnings of approximately $2.6 million (3.1 billion won) in the second quarter, while Coinone contributed $1.5 million (1.78 billion won) throughout the financial year.

The Shinhan Bank–Korbit partnership reported the lowest earnings of almost $0.3 million in the last quarter.

Chang-hyun highlighted that the South Korean market saw a fivefold increase in the number of user accounts this year alone, adding:

“Compared to the beginning of the year, the balance of deposits has quadrupled, and the coin craze has not yet ended, with Bitcoin prices recently surging again.”

Comparing the total amount of deposits attributed to real-name accounts for crypto trading, South Korea saw an increase of 316%, having brought up the investment from 2020’s $1.47 billion (1.7 trillion won) to $6.14 billion (7.08 trillion won) by the end of July 2021.

Related: South Korea to take action against unregistered crypto exchanges

South Korean regulators have recently issued a warning to crypto exchanges to have voluntarily registered with local authorities by Sept. 24. The warning has been issued to all crypto exchanges that make use of the Korean language, Korean won or that serve the Korean market.

The punishment for entities that don’t follow suit will face prison time of up to five years or a fine of up $43,500 (50 million won).