This is actually a lot more common than you would think. I knew a oil prospector that 'struck it rich' but had his line of credit called on him by the Bank of Montreal because they didn't think he could handle setting up that many oil rigs at once. Nearly drove the guy out of business. He ended up suing them (he was successful in an out of court settlement and ONLY because BMO called it within 30 days instead of the 60 days specified in his contract) and to this day refuses to sign any agreement with any financial institution without his lawyer rewriting everything.