This research focuses on the issue of financial reporting opacity among telecommunications sector firms in the Iraq Stock Exchange (ISX) during 2020–2024. It uses Parkinson Measure as a specialized quantitative instrument for measuring true stock-price volatility from daily high and low price values, considering it as a diagnostic of informational opacity in financial statements. Such is the case for the Parkinson Measure, which is a specialized quantitative tool to calculate actual stock price volatility from daily high and low values of stock price, considered as a diagnostic of the informational opacity within financial statements. The study comprises two telecommunications firms : Asia Cell Telecommunications and Al-Khatam Telecommunications (Zain Iraq), based on a dataset of 310 daily observations spread over an event window of 31 trading days per year (15 days pre-disclosure + disclosure day + 15 days post-disclosure), resulting in 10 main analytical observations. This paper uses descriptive statistics, Pearson correlation analysis, simple linear regression, and paired-samples T-Test to identify significant changes in the variables of the study between the two periods. The results indicate that there were significant differences in the levels of financial reporting opacity between the pre-and post-disclosure periods (Sig = 0.045), suggests that the findings of financial reports are informative, and affect the life of the market in Iraq. Conversely, there are no significant differences were found in the investor decisions (volume traded) for the two periods (Sig = 0.09). In addition, opacity and investor decisions were not even close to being statistically significant, however the evidence shows a rather strong positive relationship (r = 0.841) between the pre- and post-disclosure volatility levels, implying that the decisions of investors are in sum, the accounting content of financial reports is affected by influences outside thereof.