Back ratio limits up to 55 became common for nonconforming loans in the 2000s, as the financial industry experimented with looser credit, with innovative terms and mechanisms, fueled by a real estate bubble. The mortgage business underwent a shift as the traditional mortgage banking industry was shadowed by an infusion of lending from the shadow banking system that eventually rivaled the size of the conventional financing sector. The subprime mortgage crisis produced a market correction that revised these limits downward again for many borrowers, reflecting a predictable tightening of credit after the laxness of the credit bubble. Creative financing (involving riskier ratios) still exists, but nowadays is granted with tighter, more sensible qualification of customers.