Investor confidence in China's securities market remains strong, data from the China Securities Investor Protection Fund Corp. (SIPF) showed.

The investor confidence index compiled by the SIPF came in at 58.1 in September, retreating 0.9 percent from August's high.

On a yearly basis, the index still marked a 15.5-percent rise. Readings above 50 signal investor optimism.

Chinese stocks have steadily moved upward since June. The benchmark Shanghai Composite Index went up 0.25 percent to close at 3,378.65 points on Friday, while the Shenzhen Component Index closed 0.44 percent higher at 11,238.88 points.

Investors have strong confidence in China's economy, both in economic policy and overseas operations, the SIPF said in a statement.

The statement said the sub-index for economic fundamentals stood at 64.8 as the economy stabilized.

Data from the National Bureau of Statistics showed China's economy continued steady expansion in the first three quarters of this year, with growth at 6.9 percent year on year, well above the government's annual target of 6.5 percent.