US Treasury bonds have a negative yield for some

Foreign pension funds have to pay a currency transaction, hedge against currency fluctuations.  That extra transaction costs make the ten year negative for Japan and Europe.  So we see that indeed, for the US the ten year rate cannot stay below 1.5% for very long.

Bloomberg: For Kaoru Sekiai, getting steady returns for his pension clients in Japan used to be simple: buy U.S. Treasuries.
Compared with his low-risk options at home, like Japanese government bonds, Treasuries have long offered the highest yields around. And that’s been the case even after accounting for the cost to hedge against the dollar’s ups and downs -- a common practice for institutions that invest internationally.
It’s been a “no-brainer since forever,” said Sekiai, a money manager at Tokyo-based DIAM Co., which oversees about $166 billion.
That truism is now a thing of the past. Last month, yields on U.S. 10-year notes turned negative for Japanese buyers who pay to eliminate currency fluctuations from their returns, something that hasn’t happened since the financial crisis. It’s even worse for euro-based investors, who are locking in sub-zero returns on Treasuries for the first time in history.