Bolstered by improving sales and better margins, profits for China's industrial companies rose in May, bucking a months-long downtrend, data from the National Bureau of Statistics revealed Thursday.

Industrial profits increased 1.1 percent year-on-year in May, to 565.6 billion yuan ($82.21 billion), reversing a 3.7 percent drop in April.

During January to May, industrial profits fell 2.3 percent compared to the same period last year. Profits had decreased 3.4 percent in January to April period.

The uptick in May was driven by quicker sales and slower increases in corporate costs, Zhu Hong of the statistics bureau said in a statement accompanying the data, adding that better margins in equipment manufacturing and the coal sector attributed to the bulk of the increase.

At the same time, liabilities of industrial firms with annual revenue more than CNY 20 million, increased 5.3 percent at the end of May.