Major Chinese industrial firms saw their combined profits rise 6.3 percent year on year in June, slowing from the 15.5-percent rate seen in May, official data said on Saturday.

The profits of industrial companies with annual revenues of more than 20 million yuan ($3.24 million) hit 502.42 billion yuan in June, the National Bureau of Statistics (NBS) said in a statement.

In the first six months, their profits rose 11.1 percent to 2.58 trillion yuan ($418.75 billion), slowing from the 12.3-percent rate seen in the first five months.

In breakdown, private businesses led the growth, with their combined profits up 15.8 percent year on year in the first half year, while State-run enterprises saw their combined profits up 4.8 percent during the period, according to the statement published by the NBS on its website.

Among 41 industries surveyed, 30 reported year-on-year profit growth in the first half year, while eight saw profit decline.

The three sectors of coal exploitation, nonferrous metal smelting and ferrous metal smelting reported remarkable decreases in profits, He said.