题　目：How do geopolitical tensions affect firms’ direction of technological change?

嘉　宾：阮宏勋 副教授 北京大学

主持人：万相伟 副教授 上海交通大学安泰经济与管理学院

时　间：2026年3月25日（周三）13:30-15:00

地　点：上海交通大学 徐汇校区安泰浩然楼306

内容简介:

This paper reveals a large and overlooked source of distortion in predictive regressions: higher-order bias. While existing corrections only address first-order bias, we show that higher- order terms in both direct regression (DR) and implication (IM) based estimators can seriously mislead both statistical and economic conclusions, especially with persistent predictors and long horizons. We then develop iBoot, a unified framework that integrates indirect inference with bootstrap methods. iBoot (i) jointly corrects first- and higher-order biases in both estimation and inference for DR and IM estimators, and (ii) applies seamlessly to both short- and long-horizon regressions. Simulations demonstrate that iBoot achieves minimal bias, accurate confidence intervals, correct test size, and high power. When applied to classic return predictors, iBoot materially changes the economic significance of return predictability. This paper thus establishes a new foundation for credible and robust estimation and inference in predictive regressions.

Technology export controls shrink the effective market for embargoed U.S.-centric technological trajectories and redirect innovative effort toward sanction–resilient alternatives. We develop a text–based Technology Redirection Score (TRS) that uses patent similarities to measure a patent’s proximity to an incumbent U.S.-led technology base relative to alternative

technology bases. We apply the measure to U.S. export controls imposed through additions of Chinese firms to the BIS Entity List. Using patent text for both U.S. and Chinese assignees, we find a pronounced decline in TRS for exposed U.S. suppliers and Chinese firms, indicating systematic redirection away from U.S.-centric stacks toward alternative trajectories. Among U.S. suppliers, patents that shift more toward alternative trajectories are valued about $3.07 million higher than otherwise comparable patents that remain on the incumbent path after sanctions. Consistent with this redirection, U.S. suppliers to sanctioned Chinese customers experience cumulative abnormal returns (CARs) of -2.93% around Entity List announcements, whereas Chinese upstream suppliers earn positive CARs of 3.48%. We also find that exposed U.S. firms experience declines in innovation output and profitability following the shock. Sanctioned Chinese entities and their domestic suppliers exhibit significant increases in both the quantity and quality of innovation. By linking stock returns, patent text, and firm-level innovation outcomes, the paper provides new micro-evidence on how technology sanctions act as a directed technical change shock, reallocating innovative activity across technological trajectories.

演讲人简介：

阮宏勋，北京大学光华管理学院金融学副教授。毕业于美国宾夕法尼亚大学沃顿商学院金融系，获金融学博士学位。研究方向是机构投资者，实证资产定价，结构性估计。阮宏勋教授的研究发表于国内外顶级学术期刊，包括The Journal of Finance, The Review of Financial Studies，以及《金融研究》。阮宏勋教授为包括金融学三大顶级期刊在内的多家国内外顶级学术期刊提供审稿服务。

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