Investor demand for yield has pushed borrowing costs for private equity portfolio companies to among their lowest this year. In February, companies were paying 13% to refinance debt in the high-yield market, but this month the cost of raising fresh borrowing came down to about 8%.

Richard Clark, a director in the debt advisory practice at DC Advisory said: "The high-yield bond markets have been very active post-summer as companies try to take advantage of the huge inflows into the asset class, driven by investors' search for yield in a low interest rate environment."