arXiv:2608.05373q-fin.TRcs.LG2026-08

通过市场状态速度的异常波动,精准识别日内期权操纵行为。

Velocity- and Regime-Aware Detection of Intraday Options Market Manipulation, with Explainable Attribution

论文配图:Velocity- and Regime-Aware Detection of Intraday Options Market Manipulation, with Explainable Attribution
图 1 · 摘自论文原文
  • 以期权德尔塔速度和价格速度为核心指标,构建分钟级检测流程。
  • 在印度银行指数期权数据中,10天操纵事件全部召回,精度接近25%。
  • 用SHAP解释每条警报,且未确认警报与已知操纵日特征高度一致。

日内市场操纵难以察觉,因其痕迹短暂、淹没于海量报价中,且统计特征与正常波动相似。现有检测器虽召回率高,却因误报过多导致精度崩溃,无法供监管使用。本文发现操纵行为留下独特动态特征:市场状态速度呈现“拉升-崩盘”模式,而非仅看水平值。我们构建基于平滑状态速度(指数期权用期权德尔塔速度,个股用价格速度)的分钟级检测流水线,采用严格时间分区策略,并通过SHAP进行可解释性归因。测试期完全外样本,阈值预先固定。在锁定的印度BANKNIFTY指数期权数据上,基础自编码器成功捕获全部10个监管标记的操纵日。引入隐马尔可夫模型推断的市场状态后,尽管状态描述区分明显,但使用其反而牺牲召回率换取精度,而在封闭世界假设下精度仍维持约25%。该动态特征同样出现在交易清淡的美国个股(SEC诉Patel案),形态可迁移,但速度幅度不可迁移。泵-反转形状得分在ARQQ和ACY上的AUC分别为0.91和0.81,且在案例中峰值落在监管文档记录的时间窗口内。对所有警报的精确SHAP归因显示,未确认警报与已确认操纵日的归因模式高度一致(余弦相似度0.99),表明精度上限源于标签不完整而非模型缺陷。跨市场与品种传递的,是动态特征本身。

原文摘要 · Abstract (English)

Intraday market manipulation is hard to detect because its footprint is brief, buried in millions of quotes, and statistically similar to ordinary volatility. Detectors reach high recall only by flagging so many other days that measured precision collapses, producing alerts no regulator can act on. We show that this manipulation leaves a distinctive dynamic signature: a pump-and-crash pattern visible in the velocity of market state, rather than its level. We build a minute-level detection pipeline, strictly partitioned in time, based on smoothed state velocity: option-Delta velocity for index options and price velocity for equities. We explain every alert with SHAP attribution. We hold the test period strictly out-of-sample and fix all thresholds before evaluation. On the locked Indian BANKNIFTY index-options test, the plain autoencoder recovers 10 of 10 regulator-identified manipulation days. Conditioning detection on market regimes inferred by a hidden Markov model yields an instructive negative result. The regimes are descriptively distinct, but using them trades recall for precision. Under the closed-world assumption that unlabeled days are normal, precision remains near 25%. The same dynamic appears in thinly traded U.S. equities (SEC v. Patel). The shape of the signature survives the transfer; its velocity magnitude does not. A pump-reversal shape score ranks the complaint's alleged manipulation days with AUC 0.91 (ARQQ) and 0.81 (ACY). On the ARQQ worked example, the score peaks inside the complaint's documented minute window. Finally, exact SHAP attribution over every alert shows that unconfirmed alerts share the regulator-identified days' attribution profile (cosine similarity 0.99). The precision ceiling is consistent with incomplete enforcement labels rather than detector failure. What transfers across markets and instrument types is the dynamic signature itself.

市场操纵动态检测可解释性期权分析

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