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 The answer may surprise you but it's Yes, banks invest heavily in bitcoin.
Here  is a non-exhaustive list of banks that invested in bitcoin in 2017:  Goldman Sachs, JP Morgan, UBS, BNP Paribas, Societe Generale, CityBank,  Barclay's.

By  investing in bitcoin, I mean either bought directly from bitcoin or  established partnerships with bitcoin and blockchain ecosystem  companies.
In  particular, 2017 saw futures trading on bitcoin (more info) on the  Chicago Stock Exchange, where investment funds and banks rushed.

Why are banks investing in bitcoin? Simply  because they understood that it had become a phenomenon too big to  ignore and that bitcoin would take a significant place on global  finance.

For  the anecdote, JP Morgan boss Jamie Dimon publicly stated in October  2017 that bitcoin was "stupid", a scam and would fire any of its  employees who traded bitcoin. The impact of the case was global, relayed in the media and bitcoin immediately dropped by 20%.
What did JP Morgan do in the wake? The same day, the bank took the opportunity to buy several million dollars of bitcoin. It  was only a manipulation of prices to buy bitcoin, which proves that he  did not think a word about what he said about bitcoin. Funny, no! 

 Bitcoin No, Blockchain Yes!

When we talk about the banks' investments, we usually talk about investing in the bank's own funds. Otherwise called own account investment. Banks  can not yet invest to my knowledge in Bitcoin in accordance with the  current regulations and compliance with the liquidity and security  ratios of the funds of the bank.

However,  according to CoinBase, some Hedge Funds have been the experts in  investing in Bitcoins since 2014. Here is the list 6 New Hedge Funds  Seeking Bitcoin Returns. Therefore, through its hedge funds, banks may have taken positions on Bitcoins and / or offered to some very wealthy clients.

Julien  Boyer is right the banks have, his last years, heavily invested in the  underlying technology of Bitcoin: BlockChain, or French block chain. To make it simple Blockchain is a secure and distributed database. Basically, we can exchange, validate, and store information, in a completely transparent way. By  extension, a blockchain is a database that contains the history of all  the exchanges made between its users since its creation.



The profits of the blockchain are both perceived as a threat and an opportunity for the banks. A telling example is the investments that large numbers of banks have made in Ripple technology. Ripple is the new technology that will allow us to make our transfer and replace Swift! As a payment and settlement protocol, large banks like Santander saw Ripple's potential early enough for a bank. In a final fundraising for 55 million, a large Asian Standard Chartered Bank was in the game. Of course, Ripple is an example among others to tell you that yes the banks invert in the Blockchain.

Good day and long live the Blockchain;)