MarketAxess Holdings reported a recovery in trading volumes across most products in May 2026, with its estimated US high-grade market share rising approximately 100 basis points to 17.8 per cent from April levels.

The electronic fixed-income trading platform operator said the improvement was driven by increased market share in the client-initiated channel. The company estimated that duplicate trade reports inflated US high-grade TRACE volumes by up to 8 per cent in May. Adjusting for these duplicates, in line with a recent FINRA proposal to suppress duplicate reporting, MarketAxess said its estimated market share would have been approximately 19.5 per cent.

Portfolio trading activity reached record levels, with US high-grade average daily volume hitting $1.4bn, up 68 per cent year on year. Total portfolio trading ADV rose 47 per cent to $2.1bn. US high-yield portfolio trading ADV increased 172 per cent to $412m, while emerging markets ADV more than doubled to $160m. The company’s estimated market share of US credit portfolio trading reached 22 per cent, compared with 16.8 per cent in the prior year.

Block trading ADV rose 17 per cent to $6bn, with US credit block ADV up 14 per cent to $3.5bn. Emerging markets block ADV increased 35 per cent to $2bn.

In dealer-initiated trading, total Mid-X volume reached a record $7bn, representing an increase of 119 per cent. Record levels of emerging markets and eurobonds ADV, both up 35 per cent, were offset by declines in US high-grade ADV.

Year-on-year and month-on-month declines in total credit variable transaction fees per million were attributed to product and protocol mix, the company said.