Growth of U.S. nonfinancial-sector corporate debt is likely to slow through 2019. Moody's said, reflecting a growing sense of macroeconomic risk and changing views of the interest rate environment.

Moody's analysts project total nonfinancial corporate debt's year-over-year growth rate to be 5.0% in the fourth quarter, after a 6.5% growth figure for the fourth quarter of 2018.

John Lonski, chief economist at Moody's Capital Markets Research, said only a profit decline that forces companies to increase borrowing to meet capital needs could push nonfinancial corporate debt growth to at least 6% annually by year-end.

Outstanding U.S. nonfinancial corporate debt grew to a record $9.759 trillion in the fourth quarter of 2018, Moody's reported. Loan debt jumped by 16.8% to a record $3.519 trillion, and bond debt increased 2.2%, to $5.497 trillion.

"The much faster growth of loan debt relative to bond debt stemmed from the stronger investor preference for variable-rate loans owing to what had been expectations of at least four more Fed rate hikes," Lonski wrote in the report.

But due to the much lower chances of a higher Federal Reserve funds rate through 2020, investor demand for variable-rate loan debt has weakened, he said.

The Fed raised rates four times in 2018 but shifted to its patient stance in January.

Moody's warned in January that global credit conditions will weaken and risks will rise in 2019 amid slowing economic growth, increasing funding costs, and escalating trade and political tensions, among other factors.