I think Luis is missing the point here by arguing this is actually a good thing cos the free market has come up with solution. Banco Popular has a history of being irresponsible with its customers money which is why the bank was insolvent and requiring intervention in the first place. All this "bail in" has done is shift the risk onto Santander. All that bad debt hasn't miraculously disappeared. If I was a Santander customer or shareholder, I'd be very concerned about this move since the deal was rushed through in 2 days with no due diligence.

I encourage you to check out Simon Black's review of this event: http://bit.ly/2r3hk9y .

Given the risk to Santander - which everyone seems to be ignoring - I also find it amazing that it's share price rose on the news. This FT article provides a good summary of the deal http://on.ft.com/2r9VTCW