Punjab National Bank in India recently was the victim of a fraud that cost the bank more than $2bn; some have argued that if the system in which the bank used was on the blockchain the fraud would not have happened or it would have been detected quickly; banks still operate on systems that don’t always connect or still involve a lot of paper; enlisting blockchain will help to make the process more efficient, transparent and safe; when this could be implemented is a different question as banks have started testing the new technology, it has yet to be widely adopted across the globe in banking. Source.