The amount of new money paid into investment funds shrunk by nearly a third during November.
Sales of UK-based unit trusts and open-ended investment trusts dropped to just 1.42bn, once people cashing in their investment or moving it elsewhere were stripped out, according to the Investment Management Association.
The latest figure is down from 2.04bn in October and ends a strong run for sales of the funds. Monthly net investments had been running at more than 2bn since June.
Investors paid a total of 21.4bn into the funds during the first 11 months of the year, compared with 23.7bn during the same period of 2010.
The group said there was no obvious reason for the fall in investment levels during November, and it was likely to reflect monthly volatility in sales.