Siam Commercial Bank (SCB), Thailand’s oldest lender, abandoned a plan to buy a majority of Bitkub Online, the country’s largest crypto exchange, citing unresolved regulatory issues in a statement on Thursday.

SCB had agreed to acquire 51% of the exchange for 17.85 billion baht (US$500 million) in November. The transaction was expected to be completed by the first quarter of 2022.

“Bitkub is currently in the process of resolving various issues as per the recommendations and orders of the Securities and Exchange Commission, Thailand, which are uncertain in terms of timeframe in resolving those issues. As a result, the Buyer and the Seller have agreed to terminate the Transaction,” Siam Commercial said.

In May the exchange was hit with fines from the Thai SEC for not complying with digital asset listing rules when adding KUB coin, the platform's native token. The SEC also told Bitkub to improve its platform after it experienced trading outages in January last year.

A due diligence investigation of Bitkub didn’t highlight any major problems, Siam Commercial said. The bank also reiterated its intention to enter into the blockchain and digital asset arena.