An article in MarketWatch warns that the mountain of corporate debt coming due by 2023—$3.3 trillion, representing 48% of all current outstanding commercial debt—could spell bumpy road ahead for the stock market.

The article cites comments from industry veteran and Heartland Advisors chief executive Will Nasgovitz: “with interest rates low, the economy strong, and relatively easy lending standards, the thinking went that borrowing to buyback shares or finance acquisitions was a low-risk strategy. But the next five years could severely test that Pollyanna view.” Nasgovitz offers the following chart to support his thesis:

“The sheer volume would be challenging for the market to digest in the best of scenarios” says Nasgovitz, adding that as banks become more stringent in their lending standards, borrowers could face higher rates to obtain the funds needed to meet debt coming due.

According to Nasgovitz, the excessive debt load presents a headwind to leveraged companies in the intermediate term, although he doesn’t currently see signs of “a full-blown financial crisis on the horizon.”