Johannesburg - Look anywhere in the world and you’ll be hard-pressed to find an investment that’s as profitable and safe as the dollar-denominated bonds of higher-rated companies in developing nations.

Their 5.6% rally this year, while not the biggest in absolute terms, eclipses more than 130 assets from UD Treasuries to gold and even bitcoin when volatility is factored in, according to data compiled by Bloomberg. The 19% jump in Colombian stocks might sound like a better deal, but price swings in Bogota exposed investors to six times more risk. When both factors are considered, the gains in emerging-market corporate dollar bonds come out twice as good, the data show.

That marks a turnaround for the securities after last year’s selloff fueled by concern higher US interest rates, currency swings and a slowdown in China’s economy would spur corporate defaults in emerging markets. Now investors are returning, buying the bonds of borrowers such as oil-company Petroleos Mexicanos and Brazilian iron-ore exporter Vale SA in a low-volatility sector yielding an average 2 percentage points more than Treasuries.