Patrick Clifford, a spokesman for Pine River at Abernathy MacGregor Group, declined to comment.
Yields on 10-year Treasuries have dropped to 2.35 percent from 3 percent in December 2013, defying analyst predictions for the opposite to happen as the Fed ended its monthly bond-buying program.
When the market does start going the other way, debt investors are counting on this $756 billion bet to protect them.