Evaluating the flow of information and its impact on investor sentiment in financial markets is a crucial issue. In this study, 3,830 news items of value, shared through mainstream media, financial magazines, official institutions, and other media channels, regarding 10 banks listed on the Borsa Istanbul Bank Index between January 2, 2018, and December 31, 2022, were coded as positive and negative and included in the data set for analysis using dummy variables. The relationship between positive news (DK1), negative news (DK2), and returns (RETURN) was analyzed using the Granger causality test. According to the Granger causality test results, negative news has a statistically significant impact on stock returns. This suggests that negative news is taken more seriously by investors and is more strongly reflected in pricing. Conversely, positive news has no significant impact on returns. This suggests that investors are more cautious about positive information or delay in reflecting it in the market. When both positive and negative news are considered together, a generally significant causal effect on returns is concluded. Consequently, it can be argued that investors are more sensitive to negative news, and such news plays a more dominant role in pricing. The analysis findings support both real market examples and the loss avoidance approaches in the theory of Negativity Bias and Expectation Theory.