Topological anomaly scores predict return curves in S&P 500 stocks
problem Detecting anomalies in financial time series
method BallMapper, decoder-conditional VAE, Function-on-Function regression
result Anomaly history carries predictive content for return curves
New study finds day-of-the-week effects in stock market returns using multifractal analysis.
problem Exploring calendar anomalies in stock markets, particularly day-of-the-week effects.
method Multifractal Detrended Fluctuation Analysis (MF-DFA) applied to daily returns of market indices.
result Monday returns exhibit more persistent behavior and richer multifractal structures than other days.
Investing in high quality firms yields excess returns, contrary to risk or behavioral explanations.
problem Excess returns of quality stocks despite risk and behavioral explanations.
method Investigated two explanations: risk and behavioral views; provided novel evidence for the behavioral view.
result Excess returns of quality stocks are not due to risk, but due to systematic underestimation by analysts.
There are some statistical anomalies in the Chinese stock market, i.e., positive return skewness, anti-leverage effect (positive returns induce higher volatility than negative returns); and reverse volatility asymmetry (contemporaneous return-volatility correlation is positive). In this paper, we first confirm the exis…
Study finds mixed evidence of monthly stock market anomalies in Turkey and US.
problem Investigating whether stock markets exhibit abnormal returns monthly.
method Statistical summary analysis, decomposition technique, dummy variable estimation, binary logistic regression.
result Weak evidence against efficient market hypothesis on monthly returns, with notable May effect in Turkey.
Detects anomalies in forest Ladar data using spectral and temporal signatures.
problem Anomaly detection in cluttered scenes using Ladar data.
method Learned subspace and coefficients for co-occurring local-patterns, modified optimization scheme for subspace learning.
result Detects spectral and temporal anomalies in FW-MSL data, supports tree species classification.
Study identifies high-density anomalies in normal data regions.
problem Detecting anomalies in normal data regions.
method Introduces non-parametric algorithmic frameworks for unsupervised detection.
result IPP framework yields the best detection results.
Useful alpha returns vanished in modern stock markets.
problem The inefficiency of modern stock markets in generating useful alpha.
method Analysis of 200 published long-short anomaly equity portfolios over different time periods and stock selection criteria.
result Even modest allowances for luck or transaction costs eliminated published academic anomalies.
The paper explains how to predict returns based on firm characteristics.
problem Predicting returns based on firm characteristics in equilibrium models.
method Reverse-engineering equilibrium construction process with linear demands in characteristics.
result Linear expressions for returns are derived from scaled net aggregate demands and their variations.
We find a rank effect in commodity prices that yields higher returns.
problem Understanding the pricing dynamics of commodities over time.
method Nonparametric econometric methods to demonstrate the rank effect as a consequence of stationary relative asset price distribution.
result A portfolio of lower-ranked, lower-priced commodities yields 23% higher annual returns than a portfolio of higher-ranked, higher-priced commodities.
We study several aspects of the so-called low-vol and low-beta anomalies, some already documented (such as the universality of the effect over different geographical zones), others hitherto not clearly discussed in the literature. Our most significant message is that the low-vol anomaly is the result of two independent…
Decision trees predict stock market returns with significant performance.
problem Finding non-linear patterns in financial data.
method Decision tree forecasting model to capture arbitrary patterns.
result Decision tree strategies achieve trading performance at 99% confidence level on S&P 500.
Extends SHAP to explain autoencoder anomalies, aiding experts.
problem Manual validation of autoencoder anomalies is challenging.
method Extends SHAP to explain autoencoder anomalies.
result Visualizes features contributing to and offsetting anomalies.
ETFs with 2x and 3x leverage underperformed the S&P 500 index due to compounding and volatility.
problem ETFs with higher leverage failed to match the performance of the underlying index.
method Analyzed the performance of leveraged ETFs compared to the S&P 500 index, accounting for compounding and volatility.
result Two-thirds of the underperformance was due to compounding and volatility, with the rest due to covariance.
Extends return extrapolation to nonlinear, asymmetric functions under stochastic volatility.
problem Behavioral anomalies in portfolio choice under stochastic volatility.
method Smooth, nonlinear, asymmetric extrapolation function; CRRA investor; Heston stochastic volatility; Hamilton-Jacobi-Bellman equation; Numerical solutions (finite-difference ADI, deep learning-driven iterative).
result Saturation acts as an endogenous correction mechanism, reducing welfare loss.
The paper resolves behavioral finance objections to rational finance theory.
problem Predictability of asset returns, Equity Premium, Volatility Puzzle.
method Statistical models within rational finance theory.
result Offers resolutions to behavioral finance anomalies.
A new framework uses information theory to detect anomalies in images without labeled data.
problem Detect anomalies in images without labeled data.
method A direct objective function using information theory to maximize the distance between normal and anomalous data.
result The proposed framework significantly outperforms state-of-the-arts on multiple benchmark datasets.
A quantitative check of weak efficiency in US dollar/German mark exchange rates is developed using high frequency data. We show the existence of long term return anomalies. We introduce a technique to measure the available information and show it can be profitable following a particular trading rule.
Topological data analysis reveals complex financial-ratio-stock return relationships.
problem Understanding the complex associations between financial ratios and stock returns.
method Topological data analysis (TDA) using the Ball Mapper algorithm.
result Interdependencies between financial ratios are often non-monotonic, offering new insights.
A robust loss for anomaly mitigation and unsupervised contamination classification
problem Detecting and mitigating contamination in supervised and unsupervised settings
method Neural Bayesian Anomaly Mitigation (NBAM)
result Recovering the structure of contamination and identifying label-flip pairs
Mid-LSTM improves midterm stock prediction accuracy.
problem Large cumulative errors in short-term deep learning models for midterm stock predictions.
method Mid-LSTM incorporates market trend as hidden states, using ARMA and LSTM.
result Mid-LSTM achieves 2-4% improvement in prediction accuracy on S&P 500 stocks.
Prototype technique for anomaly detection in industrial big data.
problem Real-time condition monitoring and failure analysis of industrial systems.
method Independent ordinations of repeated bootstrapped partitions and inspection of ordinal distances.
result Prototype technique operates at industrial scale for anomaly detection.
Study finds anomalies in high-frequency S&P 500 price changes.
problem Anomalies in high-frequency S&P 500 price changes.
method Using NBBO event-time data, the study forms pairs of backward and forward price increments, standardizes them, and estimates expected responses on a fine grid of push magnitudes.
result Persistent structural shift in expected responses: near zero for short lags, pronounced tails for long lags, indicating correlation between larger historical pushes and nonzero responses.
Investigates how extreme temperature events affect global equity portfolios.
problem Impact of extreme temperature events on global equity portfolios.
method Panel regression analysis and multi-objective portfolio optimization.
result Extreme temperature events negatively impact most sectors' returns.
We present extensive evidence that ``risk premium'' is strongly correlated with tail-risk skewness but very little with volatility. We introduce a new, intuitive definition of skewness and elicit an approximately linear relation between the Sharpe ratio of various risk premium strategies (Equity, Fama-French, FX Carry,…
We find a sharp local maximum in cross-correlation of EUR/USD and BTC/USD pairs, indicating short-term momentum trading.
problem The Epps effect is observed in various markets but deviates in foreign exchange and cryptocurrency markets.
method We document and analyze the cross-correlation function of EUR/USD and BTC/USD pairs to identify the Epps effect deviation.
result The sharp local maximum in cross-correlation function reveals the activity of short-term momentum traders.
The true probability of a European call option to achieve positive return is investigated under the Black-Scholes model. It is found that the probability is determined by those market factors appearing in the BS formula, besides the growth rate of stock price. Our numerical investigations indicate that the biases of BS…
The study reveals distinct patterns in retail investors' holding periods affecting stock returns.
problem Understanding the impact of retail investors' investment horizons on stock returns.
method Using self-reported holding periods from StockTwits, the study categorizes retail investors into long-horizon and short-horizon groups and analyzes their return patterns.
result Long-horizon retail investors exhibit underreaction to earnings announcements, while short-horizon investors show overreaction.
Study detects unusual trading patterns on crypto exchanges using complexity measures.
problem Detecting artificial trading activity on cryptocurrency exchanges.
method Complexity and statistical-structure measures derived from high-frequency trade-level data.
result Unusual trading patterns detected on Bitget for BTC and ETH after mid-May 2025.
Paper uses machine learning to analyze stock market anomalies, predicting drift direction and portfolio performance.
problem Capturing dynamics of Post-Earnings-Announcement Drift (PEAD) using machine learning.
method Uses Extreme Gradient Boosting (XGBoost) with genetic algorithm optimization to analyze PEAD dynamics.
result Demonstrates how PEAD dynamics are influenced by different factors across sectors and quarters.
We develop a theoretical trading conditioning model subject to price volatility and return information in terms of market psychological behavior, based on analytical transaction volume-price probability wave distributions in which we use transaction volume probability to describe price volatility uncertainty and intens…
Extended Chiarella model explains coexistence of trend and value in financial markets.
problem Coexistence and interaction of trend and value anomalies in financial markets.
method Extended Chiarella model with noise traders and fundamentalists, calibrated using Bayesian filtering.
result Extended model reproduces non-monotonic relation between past trends and future returns, leading to bimodal mispricing distribution.
Improves anomaly detection with contaminated unlabeled data.
problem Weakness in existing semi-supervised anomaly detection methods when unlabeled data contain anomalies.
method Integrates positive-unlabeled learning with deep anomaly detection models.
result Achieves better detection performance on various datasets.
End-to-end anomaly detection framework using labeled anomalies.
problem Limited deep learning for anomaly detection and inefficiency of existing methods.
method Deviation learning neural network with labeled anomalies and prior probability.
result Significantly better anomaly scoring than state-of-the-art methods.
PReNet detects seen and unseen anomalies using pairwise relations.
problem Detecting unseen anomalies in semi-supervised learning.
method Pairwise Relation prediction Network (PReNet) learns anomaly and normal patterns.
result PReNet significantly outperforms nine competing methods in anomaly detection.
CANARI detects near-anomalies to predict future anomalies proactively.
problem Uncertainty in anomaly detection near distribution boundaries.
method Christoffel-based ANomaly Anticipation for eaRly dIscovery (CANARI) method.
result CANARI outperforms baseline methods in detecting near-anomalies and predicting future anomalies.
Proposes a method for anomaly detection with inexact labels.
problem Handling anomaly detection with inexact labels.
method Trains an anomaly score function using a neural network-based unsupervised method, maximizing the inexact AUC.
result Improves anomaly detection performance with inexact labels and outperforms existing methods.
We extend return extrapolation to incorporate asymmetry and saturation, finding that asymmetric nonlinear extrapolation leads to lower welfare loss.
problem Optimal portfolio choice under stochastic volatility
method Smooth, nonlinear extrapolation function with sentiment and variance hedging
result Lower welfare loss with asymmetric nonlinear extrapolation
Detects anomalies relative to typical observations.
problem Common anomaly detection methods fail for frequent anomalies.
method Relative anomaly detection, considering location relative to typical observations.
result Effective for frequent anomalies, computationally feasible, real-time detection.
The S&P500 daily values and log-returns fail to conform to Benford's laws, revealing underlying trends.
problem Testing financial data for conformity to Benford's laws.
method Analyzed S&P500 daily closing values and log-returns over 16,265 days, disaggregating at five levels.
result S&P500 daily values show a huge lack of conformity to Benford's laws, with missing first and first two digits.
Deep RL detects anomalies from few labeled examples and large unlabeled data.
problem Anomaly detection with limited labeled data and large unlabeled data.
method Deep reinforcement learning to optimize detection of labeled and unlabeled anomalies.
result Significantly outperforms state-of-the-art methods on 48 real-world datasets.
A new method assigns anomaly scores to features for better interpretation.
problem Interpreting anomaly scores from feature attributions.
method Proposes a characteristic function to attribute anomaly scores using Shapley value.
result Demonstrates the potential utility of the proposed attribution methods.
Efficient method detects point and collective anomalies in data sequences.
problem Efficiently identifying anomalies in data sequences, especially collective anomalies.
method CAPA: a computationally efficient approach for detecting collective and point anomalies.
result CAPA is consistent at detecting collective anomalies and has close to linear computational cost.
DPLS improves asset pricing by capturing non-linear risk factor structures.
problem Estimating asset pricing models with non-linear risk factor structures.
method Deep Partial Least Squares (DPLS) for dynamic and flexible factor modeling.
result DPLS models outperform linear models in asset pricing, capturing non-linear risk factor interactions.
Ensemble learning improves anomaly detection for milder symptoms.
problem Difficulty in detecting incipient anomalies due to similarity to normal conditions.
method Utilize uncertainty information from ensemble learning to identify misclassified incipient anomalies.
result Ensemble learning methods show improved performance on incipient anomaly detection.
New anomaly estimator reduces bias in MLE for normally distributed data.
problem Bias in Maximum Likelihood Estimation of structured anomalies.
method Derive a new anomaly estimator using a mixture model.
result New estimator is asymptotically unbiased regardless of anomaly family size.
TPA-AD detects axle-box bearing anomalies using pseudo anomalies near normal boundaries.
problem Detecting axle-box bearing anomalies with only normal training data.
method Two-stage approach: pseudo anomalies, contrastive learning, KNN.
result Improves anomaly detection separability and sensitivity to degradation.
Paper proposes RAN for better anomaly detection in time series data.
problem Anomaly detection algorithms often fail to accurately detect anomalies due to incomplete reconstruction of anomaly data.
method RAN uses adversarial learning and latent vector-constrained Autoencoder to ensure consistent reconstruction of anomaly data.
result RAN outperforms other algorithms in detecting meaningful anomalies with higher AUC-ROC scores.