That's untrue and bad advice. The reality is that it depends (from country and bank), but often banks will have a margin call clause in the contract. In my expe

That's untrue and bad advice. The reality is that it depends (from country and bank), but often banks will have a margin call clause in the contract. In my experience they almost always have such a clause to cover their own ass. They'll not use it for relatively self contained cases, but when the shit hits the fan and there's a 2008 style downturn, they will, because they want to protect their balance sheets. This clause will then hit you at the worst possible time, when the economic situation is just bad everywhere and you'll be expected to prop up your mortgage, only you can't if you have no cash and nobody will lend you because you are in negative equity.