专业服务板块9月3日跌1.87%，钢研纳克领跌，主力资金净流出1.23亿元

Market Overview - The professional services sector experienced a decline of 1.87% on September 3, with Steel Research Nack leading the drop [1] - The Shanghai Composite Index closed at 3813.56, down 1.16%, while the Shenzhen Component Index closed at 12472.0, down 0.65% [1] Individual Stock Performance - Lan Sheng Co., Ltd. (600826) saw a significant increase of 5.62%, closing at 12.41 with a trading volume of 554,300 shares and a turnover of 681 million yuan [1] - Steel Research Nack (300797) led the decline with a drop of 6.73%, closing at 18.28 with a trading volume of 307,900 shares and a turnover of 576 million yuan [2] - Other notable declines included Shilun Testing (301228) down 6.07% and Guoyi Bidding (650168) down 5.82% [2] Capital Flow Analysis - The professional services sector experienced a net outflow of 123 million yuan from institutional investors, while retail investors saw a net inflow of 105 million yuan [2] - The table of capital flow indicates that the largest net inflow from retail investors was in the stock of Lan Sheng Co., Ltd. (600826) with a net inflow of 36.58 million yuan [3] - Conversely, Steel Research Nack (300797) had a significant net outflow from institutional investors amounting to 63.15 million yuan [3]