The economic orthodoxy of austerity means that governments facing recession can't just spend their way out of it by creating New Deal-like stimulus that gets the economy moving again: instead, they handed trillions to banks and then watched in dismay as the banks failed to lend any of that out to small businesses and entrepreneurs.
To stop banks from hoarding cash, central banks have introduced negative interest rates, meaning that banks need to pay to lend money to governments (generally the cheapest way to hoard one's cash). The idea that you can make not-lending so costly that lending starts up again is the fiscal equivalent of pushing string, and the banks hate it.
It turns out they have other options, too.
European banks are now exploring the logistics of hiding billions in cash in giant, secure, insured vaults. There's a tipping point where negative-yield bonds cost more than vaults (and that tipping point draws nearer as the business of sticking cash under the mattress gets standardised, with boilerplate insurance packages and economies of scale from new secure storage companies that offer to hold many banks' money for them in a single, cost-effective hollow mountain).
It's a funny throwback in the age of digital money: suddenly, Scrooge McDuckian mountains of cash are becoming the, ahem, gold standard. There's a heist movie in there, somewhere.
Banks look for cheap way to store cash piles as rates go negative
[Claire Jones and James Shotter/CNBC/Financial Times]
(via Naked Capitalism)