Market Performance - The three major indices opened mixed on December 17, with the Shanghai Composite Index down by 0.06%, the Shenzhen Component Index up by 0.1%, and the ChiNext Index up by 0.03% [1] Sector Performance - The retail concept, aquaculture, and non-ferrous metals sectors showed the highest gains [1] - The commercial aerospace concept, controllable nuclear fusion concept, real estate, media and entertainment, and oil sectors experienced the largest declines [1]