Manufacturing companies' profitability - as measured by their net rate of return - was estimated at 9.3% in the first quarter of 2014, down from 11.8% in the previous quarter.
This compared with 15% for service companies, according to the Office for National Statistics (ONS).
However, the ONS warned: "The estimates of net rate of return for the manufacturing sector can be quite volatile. Variation from one quarter to the next usually reflects the fortunes of a number of the larger companies and is not necessarily an indicator of improving or worsening economic performance across the sector as a whole."
Overall, private non-financial corporations' profitability was estimated at 11.9% in the same period. This was at the higher end of the quarterly range during the last five years, but lower than the rates in 2008. It was also lower than the fourth quarter of 2012 (estimated at 12.1%).