They found that it made sense to buy long bonds in almost all interest-rate scenarios but one: when rates are low (so the risk that they will revert to the mean, thus undercutting the value of the bond, is high) and the yield curve a line drawn through the interest rates on government securities with different maturities is flat (so there is little extra reward for taking that risk).

ECONOMIST: Buttonwood

The Fed is highly leveraged and faces the risk of significant losses on its portfolio of MBS and longer-term government securities once interest rates rise, as they must.

FORBES: The Limits Of Monetary Policy Call For Moral, Sound Money

If in the process of preserving those cash flows, the politicians who get them block the raising of the debt ceiling, we could experience a sell-off in U.S. government securities which would raise interest rates here and could put the brakes on economic growth globally.

FORBES: Pushing U.S. Closer to the Brink