There are some problems that not even $10 trillion can solve.

That gargantuan sum of money is what central banks around the world have spent in recent years as they have tried to stimulate their economies and fight financial crises. The tidal wave of cheap money has played a huge role in generating growth in many countries, cutting unemployment and preventing panic.

But it has not been able to do away with days like Monday, when fear again coursed through global financial markets. The main causes of the steep declines in stock and bond markets were announcements out of Greece and Puerto Rico.

And in China, the precipitous declines in its stock market were also a sobering reminder that stubborn problems lurked in the global economy.

Stifling debt loads, for instance, continue to weigh on governments around the world. Greece’s government has repeatedly called for relief from some of its debt obligations, and Puerto Rico’s governor said on Sunday that its debt was “not payable.” Both borrowers are extreme cases, but high borrowing, either by corporations or governments, is also bogging down the globally significant economies of Brazil, Turkey, Italy and China. And economists say that central banks and their whirring printing presses can do only so much to alleviate the burden.