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We study tail risk dynamics in high-frequency financial markets and their connection with trading activity and market uncertainty. We introduce a dynamic extreme value regression model accommodating both stationary and local unit-root…

Econometrics · Economics 2023-01-05 Julien Hambuckers , Li Sun , Luca Trapin

In this paper we develop a novel inferential approach based on geometric records for estimating the tail index of heavy-tailed distributions. We construct a maximum likelihood estimator for the Pareto model and establish its strong…

Statistics Theory · Mathematics 2026-04-30 Martín Alcalde , Raúl Gouet , Miguel Lafuente , F. Javier López , Gerardo Sanz

In the realm of high-dimensional data analysis, the estimation of covariance matrices is a fundamental task, and this holds true for interval-valued data as well. However, there is no unified definition for the covariance matrix of…

Methodology · Statistics 2026-04-02 Wan Tian , Wenhao Cui , Rui Zhang , Bingyi Jing , Yang Liu , Yijie Peng

We consider the fitting of heavy tailed data and distribution with a special attention to distributions with a non--standard shape in the "body" of the distribution. To this end we consider a dense class of heavy tailed distributions…

Statistics Theory · Mathematics 2017-05-15 Mogens Bladt , Leonardo Rojas-Nandayapa

In optimal covariance cleaning theory, minimizing the Frobenius norm between the true population covariance matrix and a rotational invariant estimator is a key step. This estimator can be obtained asymptotically for large covariance…

Information Theory · Computer Science 2023-05-01 Christian Bongiorno , Marco Berritta

We investigate the high-dimensional properties of robust regression estimators in the presence of heavy-tailed contamination of both the covariates and response functions. In particular, we provide a sharp asymptotic characterisation of…

Statistics Theory · Mathematics 2024-06-03 Urte Adomaityte , Leonardo Defilippis , Bruno Loureiro , Gabriele Sicuro

Natural data are often long-tail distributed over semantic classes. Existing recognition methods tackle this imbalanced classification by placing more emphasis on the tail data, through class re-balancing/re-weighting or ensembling over…

Computer Vision and Pattern Recognition · Computer Science 2022-05-03 Xudong Wang , Long Lian , Zhongqi Miao , Ziwei Liu , Stella X. Yu

We study the design of portfolios under a minimum risk criterion. The performance of the optimized portfolio relies on the accuracy of the estimated covariance matrix of the portfolio asset returns. For large portfolios, the number of…

Portfolio Management · Quantitative Finance 2016-01-20 Liusha Yang , Romain Couillet , Matthew R. McKay

The masses of data now available have opened up the prospect of discovering weak signals using machine-learning algorithms, with a view to predictive or interpretation tasks. As this survey of recent results attempts to show, bringing…

Statistics Theory · Mathematics 2026-05-06 Stephan Clémençon , Anne Sabourin

We obtain an uniform tail estimates for natural normed sums of independent random variables (r.v.) with regular varying tails of distributions. We give also many examples on order to show the exactness of offered estimates and discuss some…

Probability · Mathematics 2012-06-22 E. Ostrovsky , L. Sirota

We suggest a robust nearest-neighbor approach to classifying high-dimensional data. The method enhances sensitivity by employing a threshold and truncates to a sequence of zeros and ones in order to reduce the deleterious impact of…

Statistics Theory · Mathematics 2009-09-02 Yao-ban Chan , Peter Hall

Under losses which are potentially heavy-tailed, we consider the task of minimizing sums of the loss mean and standard deviation, without trying to accurately estimate the variance. By modifying a technique for variance-free robust mean…

Machine Learning · Statistics 2024-02-12 Matthew J. Holland

Analysis of matrix-variate data is becoming increasingly common in the literature, particularly in the field of clustering and classification. It is well-known that real data, including real matrix-variate data, often exhibit high levels of…

Methodology · Statistics 2024-07-30 Abbas Mahdavi , Narayanaswamy Balakrishnan , Ahad Jamalizadeh

Some new survival distributions are introduced based on a generalised exponential function. This class of distributions includes heavy-tailed generalisations of exponential, Weibull and gamma distributions. Properties of the distributions…

Methodology · Statistics 2014-12-03 Rose Baker

A theoretical expression is derived for the mean squared error of a nonparametric estimator of the tail dependence coefficient, depending on a threshold that defines which rank delimits the tails of a distribution. We propose a new method…

Methodology · Statistics 2023-07-25 Matthieu Garcin , Maxime L. D. Nicolas

This article is devoted to the study of tail index estimation based on i.i.d. multivariate observations, drawn from a standard heavy-tailed distribution, i.e. of which 1-d Pareto-like marginals share the same tail index. A multivariate…

Statistics Theory · Mathematics 2014-04-10 Stéphan Clémençon , Antoine Dematteo

Linear regression is arguably the most fundamental statistical model; however, the validity of its use in randomized clinical trials, despite being common practice, has never been crystal clear, particularly when stratified or…

Methodology · Statistics 2023-02-14 Wei Ma , Fuyi Tu , Hanzhong Liu

There has been a surge of interest in developing robust estimators for models with heavy-tailed and bounded variance data in statistics and machine learning, while few works impose unbounded variance. This paper proposes two type of robust…

Machine Learning · Statistics 2022-10-12 Lihu Xu , Fang Yao , Qiuran Yao , Huiming Zhang

We propose a method for estimating a covariance matrix that can be represented as a sum of a low-rank matrix and a diagonal matrix. The proposed method compresses high-dimensional data, computes the sample covariance in the compressed…

Methodology · Statistics 2017-04-04 Gautam Sabnis , Debdeep Pati , Anirban Bhattacharya

Pairwise likelihood is a useful approximation to the full likelihood function for covariance estimation in high-dimensional context. It simplifies high-dimensional dependencies by combining marginal bivariate likelihood objects, thus making…

Methodology · Statistics 2024-07-25 Alessandro Casa , Davide Ferrari , Zhendong Huang