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Research

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

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

Abstract

In our recent work Neural Portfolio Allocators: Cross-Asset Optimization Strategies with Attention-Based Transformers and Multi-Agents[1], we demonstrated that attention-based transformer architectures outperform recurrent neural networks (RNNs) and long short-term memory models (LSTMs) on long-horizon financial forecasting and allocation tasks. Building on that foundation, this study investigates (i) multiple transformer architectures to determine which are most effective across asset classes and time horizons, and (ii) how tokenization, the variable underlying each transformer variant, directly shapes inductive bias and performance. We therefore conduct a controlled ablation of point-wise, patch-wise, and variate-wise encoders, spanning equities, fixed income/rates, commodities, derivatives, and alternative assets.

Utilizing the same cross-asset dataset as in our previous study, we evaluate point-wise baselines, PatchTST, iTransformer, Crossformer-Lite, Autoformer, Fedformer, Informer, TimesNet, TimeXer, and non-stationary extensions. Tsallis entropy, employed explicitly as a regularizer in our earlier allocator, remains implicit here through normalized return distributions and tokenized features, preserving a non-extensive statistics framework suited to fat-tailed financial returns. While we do not rerun MGARCH, our volatility aware preprocessing (lookback windows, normalization) serves as a structural holdover. Likewise, synthetic datasets with independent versus dependent variates reprise the role of GBM baselines by providing control cases for separating signal from noise. By fixing data, splits, costs, and evaluation protocols, we isolate the contribution of tokenization and encoder design to predictive accuracy, risk-adjusted returns, and robustness across market regimes. Preserving the same portfolio construction pipeline and evaluation metrics as before ensures comparability. Our findings provide a systematic map of which transformer architectures and tokenization schemes are most effective across horizons and asset classes, offering practical guidance for deep sequence modeling in financial allocation.

Keywords

PatchTST, Crossformer, Autoformer, Fedformer, Informer, TimesNet, TimeXer, Tokenization, Financial Time Series, Sequence Model, Machine Learning, Neural Network, Deep Learning, Reinforcement Learning, Non-linearity in Financial Markets, I-transformer, Transformer Architectures, Tsallis Entropy, Multivariate Generalized Autoregressive Conditional Heteroskedasticity, MGARCH, Geometric Brownian Motion, Continuous-time Stochastic Process, Point-wise encoders, Patch-wise encoders, Variate-wise encoders, Hybrid encoders, Cross-lite encoders, Entropy, Volatility Regimes, Artificial Intelligence, Tsallis Continuity, TSMixup, Data Augmentation for Time Series, Elasticity of Error Utility

JEL Classification

C45, C53, C58, C63, C52, C15, C14, C22, C32, C38, G11, G12, G17, G15, G23, G32, G01, D81, D83, E44

Suggested Citation

Coulter, Nathaniel, Tokenization and Transformer Architectures for Cross-asset Allocation: Controlled Ablation in Financial Time Series (October 27, 2025). Available at SSRN: https://ssrn.com/abstract=6934938 or http://dx.doi.org/10.2139/ssrn.6934938

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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