Wall Street has long existed as a parallel universe where leaders cast by critics in the media as autocratic villains can be feted as heroes if their actions bode well for the economy. Lately, this split has reached new extremes.

In the critics’ view, we live in an increasingly illiberal age, populated by dangerously erratic strongmen. Leading examples include President Jair Bolsonaro of Brazil, who at the United Nations this week defiantly defended his government against charges that it is turning a blind eye as the Amazon burns; President Abdel Fattah el-Sisi of Egypt, whose tough, military-backed regime has been the target of protests over the past week; and Prince Mohammed bin Salman of Saudi Arabia, widely reviled for the assassination of the journalist Jamal Khashoggi by Saudi operatives.

Yet global investors view the same trio as promising economic reformers, following a mainstream playbook that could have been written (indeed sometimes is written) by analysts at the International Monetary Fund. Markets reward them accordingly. For much of their recent tenures, Brazil under Mr. Bolsonaro and Saudi Arabia under Prince Mohammed have all ranked among the world’s hottest stock markets. Until this week, this year’s top-performing market was Egypt.

The harsh reality is that markets are amoral, instinctively neutral barometers of economic performance, and they will at times ignore the brutality and excesses of strongmen for a simple reason: Facing little or no resistance from legislatures, courts or independent watchdogs, strongmen can push through sweeping reforms — particularly in emerging economies, where political institutions and the rule of law are relatively weak. Looking at the records for 150 countries between 1950 and 2010, I found 43 cases in which an economy grew at an annual pace of 7 percent or more for a full decade. An astonishing 35 of those economies — more than 80 percent of them — were run by an autocrat.