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Cover of Nathaniel Coulter's ItôFormer Published Research Paper
01

ItôFormer: Augmenting Stochastic Validity in Financial-centric Deep Neural Networks

DOI: dx.doi.org/10.2139/ssrn.6742840

Cover of Nathaniel Coulter's Tokenization and Transformer Architectures Published Research Paper
02

Tokenization and Transformer Architectures for Cross-Asset Allocation: Controlled Ablation in Financial Time Series

DOI: dx.doi.org/10.2139/ssrn.6934938

Cover of Nathaniel Coulter's Neural Portfolio Allocators Published Research Paper
03

Neural Portfolio Allocators: Cross-Asset Optimization Strategies with Attention-Based Transformers and Multi-Agents

DOI: dx.doi.org/10.2139/ssrn.5447734

Cover of Nathaniel Coulter's Modeling Nonlinear Pharmacokinetics Published Research Paper
04

Modeling Nonlinear Pharmacokinetics: Clinical v. Anecdotal Data (LGD-4033) Why Dosage Is Not the Same as Exposure!

DOI: dx.doi.org/10.2139/ssrn.6934521

Cover of Nathaniel Coulter's Quantamental Portfolio Allocators Published Research Paper
05

Quantamental Portfolio Allocators: Deriving Alpha from Fundamental Metrics with ML

DOI: doi.org/10.2139/ssrn.6934778

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Research / Publication SSRN / ONLINE JOURNAL
View at SSRN Elsevier

ItôFormer: Augmenting Stochastic Validity in Financial-centric Deep Neural Networks

Abstract

This study proposes ItôFormer, a finance-native transformer architecture rooted in Itô Calculus[1], that enforces stochastic validity within attention-based[2] sequence models. Unlike standard calculus, which deals with smooth and predictable functions; Itô's Lemma extends the chain rule to account for the non-zero quadratic variation of random processes encountered in stochastic differential equations[3].

While transformers have achieved state-of-the-art results in NLP and vision, our previous work has shown that vanilla architectures do not map cleanly onto financial time series, which are inherently stochastic and non-stationary[4, 5]. These limitations arise from mismatched design assumptions, such as deterministic sequence mappings, lack of variance modeling, and weak treatment of temporal causality.

To address this gap, ItôFormer integrates domain specific inductive biases inspired by stochastic calculus: quadratic variation-aware attention, martingale consistency constraints, and no-arbitrage penalties for options and rates. We evaluate ItôFormer across equities, fixed income, derivatives, and commodities, benchmarking against leading transformer variants from our previous works, such as: PatchTST, iTransformer, Crossformer, Autoformer, Fedformer, Informer, TimesNet, and TimeXer. Our results demonstrate that ItôFormer reduces forecast error, improves hedging stability, and enforces structural consistency absent from prior architectures. For an in depth comparison between each of the afformentioned architectures, see: "Tokenization and Transformer Architectures for Cross-Asset Allocation: Controlled Ablation in Financial Time Series[4].

Keywords

Stochastic Calculus, Financial Machine Learning, Transformer Models, Quantitative Finance, Financial Engineering, Financial Mathematics, Neural Stochastic Differential Equations, Neural Networks, Deep Neural Networks, Machine Learning, Applied Machine Learning, Applied Mathematics, Itô Calculus, Itô's Lemma, Time Series Forecasting, Deep Learning for Finance, Arbitrage-aware Modeling, Martingale Constraints, Martingale Consistency, Volatility Surface Modeling, Implied Volatility Modeling, Neural SDEs, Stochastic Differential Equations, Financial Time Series, Attention Mechanisms, Stochastic Processes, No-arbitrage Regularization, Options Pricing, Computational Finance

JEL Classification

C45, C53, G17, G12, C63, G13, C02, C58, E43

Suggested Citation

Coulter, Nathaniel, ItôFormer: Augmenting Stochastic Validity in Financial-centric Deep Neural Networks (October 30, 2025). Available at SSRN: https://ssrn.com/abstract=6742840 or http://dx.doi.org/10.2139/ssrn.6742840

Repository

github.com/Nathaniel-Coulter

Declaration of Interest

The author declares no competing financial interests, commercial affiliations, or personal relationships that could have appeared to influence the work reported in this paper.

Ethics Approval

This study did not involve human subjects research, clinical interventions, patient recruitment, or access to protected health information. All clinical data were obtained from publicly available published literature, and anecdotal observations were derived from publicly available self-reported sources that were anonymized and analyzed in aggregate for educational and research purposes. Accordingly, institutional review board (IRB) approval was not required.

Funder Statement

This research received no external funding and was conducted independently by the author.

License Information

SSRN

The copyright holder has granted SSRN a license. All rights reserved. No reuse allowed without permission.

GitHub

MIT License

Copyright (c) 2025 Nathaniel Coulter

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