“Yields on 10-year US corporate bonds have fallen to the lowest levels in history as a result of central bank liquidity, halving from 4pc to well under 2pc since early 2011.  Fitch said a ‘sudden rise’ would devastate the portofolios of life insurers, pension funds, and other fixed-income institutions. ‘If interest rates were to revert rapidly, a typical BBB-rated US corporate bond could lose 15pc of its market value, with longer duration bonds suffering a 26pc loss,’ it said.  Fitch said the authorities face an ugly dilemma. If they persist with ultra-loose policies, they will push investors deeper into ‘low-coupon securities’ that are most vulnerable to rising yields.”