Ever since Federal Reserve Chairman Jerome Powell struck a more dovish tone late in 2018, U.S. Treasury yields have fallen considerably. 

But yields are now far lower than most expected them to be by this point. 

The 10-year Treasury note's yield hit its lowest level since Jan.16, 2018, when it was at 2.538%. The 10-year yield briefly hit 2.564% Thursday morning, before settling at roughly 2.58%. Meanwhile, the one-year Treasury yield is at 2.566%, causing the two yields to be dangerously close to inverting. Bond yields fall as bond prices rise. 

"This is a classic flight to quality," Charlie Ripley, assistant vice president of capital markets and trading at Allianz investment Management, told TheStreet. Fears of slowing global economic growth have hit markets recently, and Thursday investors are particularly concerned about demand in the Chinese economy, as Apple Inc. (AAPL) - Get Report said sales in China will likely come in lower than initially expected.

"While we anticipated some challenges in key emerging markets, we did not foresee the magnitude of the economic deceleration, particularly in Greater China," Apple CEO Tim Cook said in a letter to investors Wednesday evening. This sent chills down stock investors' spines, as the Dow Jones Industrial Average lost as much as 600 points Thursday. All three major U.S. indices were down, as investors were flooding into Treasuries, regarded as among the safest investments. 

On top of the Apple news, the ISM manufacturing survey had a reading of 54.1 for the month of December, short of economists estimates of 57.9. While 271,000 jobs in the private sector were added in December, handily beating estimates of 180,000, investors are looking at the glass as half empty. "You've been having snippets of good news -- a lot of it has been overlooked by the uncertainty," Ripley said. 

The 10-year yield hit 3.2% in early November just before the Federal Reserve eased up on its position that it should raise rates as many as four times in 2019. The latest commentary from the central bank indicated as many as two rate hikes, but bond investors now seem to be pricing in zero hikes. Intensifying fears of a looming recession may even raise questions about monetary stimulus.

"There's potential for that -- it really depends on how deep a recession the U.s. economy potentially goes into," Ripley said. 

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