The Shanghai Composite Index (SCI) posted a small gain yesterday, boosted by a Wall Street rally, AP reported. The SCI closed at 18.72 points, or 0.6% higher on Wednesday, after falling 4.1% to a one-year low in the previous trading session. The Shenzhen Composite Index, meanwhile, closed down 4.4% at 973.13 points. The performance of mainland markets contrasted with markets in New York, where the Dow Jones Industrial Average gained 3.19% to close at 12,654.36 points. Analysts suggested that the weak performance of Chinese markets is due to a lack of investor confidence in the prospects for market gains.