U.S. corporate investment-grade issuance reached a record $1.346 trillion Monday, surpassing 2017's full-year total in less than eight months amid seemingly endless investor appetite following the Federal Reserve's unprecedented steps to bolster liquidity.

The Fed's March pledge to use its near limitless balance sheet to buy corporate bonds has lifted nearly every corner of the market, allowing struggling cruise lines, plane makers, and hotels to tap much-needed financing while providing top-rated companies—from Alphabet Inc. to Visa Inc. and Chevron Corp.—access to some of the cheapest funding ever seen.

Just five months ago, this kind of issuance was virtually unimaginable. The market was frozen as the coronavirus ravaged the United States and brought the economy to a standstill. But following the central bank's intervention, demand quickly returned and hasn't waned since. The Bloomberg Barclays U.S. Aggregate Corporate index reached a record-low 1.82 percent in early August, down from more than 4.5 percent in March.