Thanks to voracious demand from yield-starved fixed income investors and rock-bottom borrowing costs courtesy of the Fed, high grade corporate issuance hit a record $348 billion in Q1 of this year and junk bond supply came in close to $93 billion during the same period. Some companies — such as heavily-indebted shale producers — have used the proceeds from bond sales to stay in business, a dynamic that’s helped to create a global, deflationary supply glut.