In 2020, as the world convulsed under Covid-19 and the global economy faced its worst recession since World War II, billionaires saw their riches reach new heights.

Now some are talking to their wealth managers about how to keep a hold of and consolidate their fortunes amid the global debris of the pandemic. Others are discussing how to preempt and navigate demands from governments, and the wider public, to pick up their share of the recovery costs...