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;)