The main reason was trading costs such as commissions and bid-ask spread; even the best stock pickers have trouble covering transaction costs, they noted.

Its sole outstanding dollar bond, the 2020s, was spotted trading with a wide bid-ask spread on Friday morning, at 8.50-11.50, or around 10.00 mid-market.

Shares of the company had not opened on the London Stock exchange at 0742 GMT, with a wide bid-ask spread of 52 pence per share.

Those wider " bid-ask spreads" would make trading more expensive for clients, but help boost Goldman's returns.

Narrowing bid-ask spreads, increasing use of electronic trading and competition for big institutional clients' business are pressuring rates-trading profits.

That could result in wide bid-ask spreads and cause the funds' intraday market prices to significantly deviate from their net asset values.

High prices can mean large bid-ask spreads and small percentage movements in stocks, making them less attractive for smaller investors to trade.

Proponents of HFT argue that the practice has led to a more efficient market and ultimately, a reduction in bid-ask spreads, benefiting all investors.

In the $8.5 trillion U.S. corporate bond sector, the average bid-ask spreads on institutional-sized trades remained above pre-crisis levels, they noted.