US stocks are being propelled to fresh highs by investors borrowing a record amount of money in a high stakes gamble that is raising concerns over the potential for a sharp correction in the five-year bull run.

With the S&P 500 registering a fresh closing peak of 1,859.45 last week, margin debt – money borrowed to buy stocks – hit a record level in January according to data from the New York Stock Exchange.

Peaks in the use of borrowed money have in the past been a precursor to big bear markets and are viewed as a warning sign. Although margin debt has been hitting record highs in recent months, it now stands at $451bn on the NYSE, a rise of more than 20 per cent over the past year and above 2007’s peak of $381bn. Five years ago it hit a low of $173bn.