Borrowing costs for sub-investment grade companies in Europe are poised to fall to the lowest since July as the European Central Bank prepares to expand its bond-buying program.

Yields on the notes fell to an average 4.74 percent from a more-than three-year high in January, according to Bank of America Merrill Lynch index data. They’re less than a basis point from this year’s low, set in April.

Investors have piled into euro-denominated notes since President Mario Draghi said the ECB would begin buying high-grade corporate debt next month as part of its stimulus measures. The resultant drop in borrowing costs in investment-grade debt has encouraged investors to seek riskier assets.

“Draghi’s announcement had a massive knock-on effect in the high-yield market,” Eden Riche, the London-based head of high yield and emerging markets syndicate at ING Bank NV, said. “The hot money will continue to chase spreads down.”

Bonds with sub-investment ratings have rallied since Draghi outlined his plan to buy corporate debt on March 10. Rexel SA’s 650 million euros of bonds due June 2023 rose to 101 cents on the euro to yield 3.25 percent Thursday, the lowest since they were sold on May 4, according to data compiled by Bloomberg. Yields on Volvo Car AB’s debut euro notes fell to 2.64 percent, also the lowest since they were sold earlier this month.

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