Group 1 - The professional engineering sector increased by 0.51% on January 26, with Tongguan Mining Construction leading the gains [1] - The Shanghai Composite Index closed at 4132.61, down 0.09%, while the Shenzhen Component Index closed at 14316.64, down 0.85% [1] - Key stocks in the professional engineering sector showed significant price movements, with Tongguan Mining Construction rising by 15.71% to a closing price of 24.82 [1] Group 2 - The professional engineering sector experienced a net outflow of 468 million yuan from institutional investors, while retail investors saw a net inflow of 254 million yuan [2] - Major stocks like Huadian Technology and Tongguan Mining Construction had varying net inflows and outflows from different investor types, indicating mixed investor sentiment [3] - The data shows that retail investors contributed positively to the net inflow, contrasting with the outflows from institutional and speculative investors [2][3]