US Big Tech firms are borrowing so heavily that bond investors are starting to view some of their emerging-market peers as safer bets.

SK Hynix Inc. bonds maturing 2031 now yield just nine basis points more than those of Amazon.com Inc, a third of year ago levels, and it’s cheaper to hedge the South Korean company’s credit risk than that of many US tech giants.

And the shift extends beyond individual companies — in a historic first, risk premiums on emerging-market corporate debt indexes are converging with comparable US benchmarks.