In recent years, easing the estate tax burden has been consistently proposed as a solution to address the “°Korea Discount.”± The central argument is that reducing the current top marginal tax rate of 50% or eliminating the surcharge on shares bequeathed tothe largest shareholder group would help mitigate the tax burden associated with rising stock prices at the time of bequest. This, in turn, is expected to encourage controlling families to focus on enhancing firm value. Another argument is that the high estate tax burden incentivizes controlling shareholders and their families to engage in tunneling as a means of transferring corporate control. As a result, the stock prices of firms involved in such practices tend to be undervalued. It is also argued that reducing the estate tax burden could help mitigate this problem. However, empirical studies supporting this claim are scarce. The only study directly addressing this topic is Yeh and Liao (2018), who conducted an event study based on the Taiwanese government's policy of reducing the top marginal estate taxrate from 50% to 10%. They found that during the [0, +5] event window, the stock prices of family-controlled firms rose by 1.44% relative to non-family firms, suggesting improved ownership structures in family firms. This study indirectly examines the effect of estatetax relief by analyzing stock price movements immediately following the assessment period for bequeathed share values, defined as two months after the valuation reference date. Prior to the end of the assessment period, stock price increases directly raise the estate tax burden, incentivizing controlling families to suppress stock prices. After the assessment period, however, this incentive disappears abruptly, producing an effect analogous to estate tax relief. This methodological approach offers several significant advantages: it allows research to be conducted even without an actual change in the top marginal tax rate, facilitates more precise estimation of event effects by leveraging the unpredictable nature of death, and expands the number of analyzable events (i.e., instances of death). To utilize this empirical research setting, we collected data on 36 deceased individuals—including group chairmen and their family members—from business groups designated for disclosure by the Korea Fair Trade Commission between 2000 and 2023. At the time of their passing, these individuals collectively held equity stakes in 73 publicly listed affiliate firms. Cases in which the decedent donated their equity holdings to public interest foundations or similar entities were excluded from the sample. Using this data, this study reveals that reducing estatetax burdens does not lead to an increase in stock prices for bequeathed shares. First, no statistically significant differences areobserved in stock price reactions between firms with bequeathed shares and those with non-bequeathed shares within the same business group immediately following the assessment period. This pattern holds consistently when examining buy-and-hold abnormal returns (BHAR) over 3-month, 6-month, and 1-year periods after the assessment. Furthermore, when comparing firms likely to increase dividends to pay estate taxes—those with bequeathed shares and those with family-owned shares but no new bequest—no statistically significant differences in stock price reactions were found. Neither the proportion of bequeathed shares nor the relative value of bequeathed stock shows a significant relationship with stock price movements. This pattern remained consistent even in firms where controlling families exert relatively greater influence on stock prices, such as those with smaller market capitalizations or lower price-to-book ratios (PBR). Similar results were also observed in post-2014 samples following amendments to the Monopoly Regulation and Fair Trade Act that curtailed unfair succession practices. Furthermore, this pattern was evident in firms where group succession was insufficiently advanced, potentially heightening incentives for stock price management. Additionally, the number of investor relations (IR) meetings, as well as R&D and capital expenditures,showed no substantial changes before or after the death of controlling shareholders, suggesting that efforts to enhance firm value were not significantly intensified following their death. Finally, while the age of controlling shareholders was associated with a decline in firm value, this trend was observed across all firms, regardless of whether the controlling shareholder held shares in the firm. This finding contrasts with the expectation that such effects would be limited to firms in which the controlling shareholder holds shares, where incentives to suppress stock prices may increase as mortality risk rises. These findings indicate that the observed decline in firm value is not the result of deliberate efforts by controlling families to suppress stock prices in response to estate tax burdens. Instead, the results challenge the argument that estate tax relief directly leads to significant stock price increases or enhanced firm value.