By some measures, 2019 was the best year for the global stock market in a decade — and the best for the American bond market since 2004.

Then, with the signing of an initial trade deal between the United States and China in mid-January, the rallies took on new energy.

When markets rise relentlessly like this, investing looks easy. But it isn’t, really.

To the contrary, markets often fall — and sometimes crash. Protecting your hard-won money can be much harder than amassing it.

The question, as always after magnificent gains, is: How much longer will this spectacular rally go on, and what can I do to protect my profits? If you weren’t lucky enough to participate in the recent rallies, you will also want to know whether this is still a good time to jump in.