BlackRock Inc. turned bullish on US Treasuries, ending a six-year underweight stance as yields hit two-decade highs. The firm upgraded short-term bonds to overweight, citing higher yields and excessive Federal Reserve tightening expectations. This shift shows how investors now seek safety in debt as market conditions change for global portfolios.

BlackRock Inc.’s research unit has turned more bullish US Treasuries, unwinding a “mainstay” underweight stance for most of the past six years, as yields climbed to the highest levels in more than two decades.

The BlackRock Investment Institute upgraded short-term Treasuries to overweight and longer-term debt to neutral from underweight, citing higher yields and potentially “excessive” expectations for Federal Reserve tightening. It also trimmed an underweight position in Japanese government bonds, according to a note by strategists Jean Boivin and Wei Li and Rick Rieder , BlackRock’s chief investment officer of global fixed income.