US Treasury Sec. Mnuchin: Negative interest rates in Europe are concerning

Commenting on the European Central Bank's (ECB) decision to lower its rate on the deposit facility by 10 basis points to -0.5%, US Treasury Secretary Mnuchin told CNBC that he was not surprised by the ECB's decision and argued that negative interest rates in Europe were concerning and that they were making it hard for the US to "have a good economy."

Regarding the possible introduction of 50-year Treasury bonds, Mnuchin noted that there was some demand for the 50-year T-bonds.

"It would be a good thing to expand the US borrowing capabilities," Mnuchin said. "We would only issue a 50-year bond if we could do it at an appropriate spread over the 30-year bond. 50-year bond is seriously on the table for next year."