Research Article

Stock Price Forecasting and Portfolio Selection Through Machine Learning: An Application on BIST Participation 30 Index

Volume: 23 Number: 3 October 15, 2025
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Stock Price Forecasting and Portfolio Selection Through Machine Learning: An Application on BIST Participation 30 Index

Abstract

This study aims to forecast stock prices of companies listed in the BIST Participation 30 Index using machine learning techniques and construct optimized portfolios based on these forecasts. Two methods, Linear Regression (LR) and Gated Recurrent Unit (GRU), were applied for price forecasting, and the results were used to create equal-weighted and return-weighted portfolios using the Markowitz mean-variance model. The analysis shows that the GRU model significantly outperforms LR in terms of forecast accuracy, leading to more profitable portfolio strategies. The return-weighted portfolio consistently showed higher performance compared to the equal-weighted portfolio and the benchmark index. These findings highlight the effectiveness of machine learning models, particularly deep learning algorithms like GRU, in enhancing investment strategies and portfolio management within the context of portfolio selection. The study provides a framework for future research to explore other indices and machine learning models.

Keywords

References

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Details

Primary Language

English

Subjects

Finance

Journal Section

Research Article

Early Pub Date

October 15, 2025

Publication Date

October 15, 2025

Submission Date

September 30, 2024

Acceptance Date

May 12, 2025

Published in Issue

Year 2025 Volume: 23 Number: 3

APA
Gözkonan, Ü. H., & Karğın, M. (2025). Stock Price Forecasting and Portfolio Selection Through Machine Learning: An Application on BIST Participation 30 Index. Journal of Management and Economics Research, 23(3), 99-121. https://doi.org/10.11611/yead.1558158
AMA
1.Gözkonan ÜH, Karğın M. Stock Price Forecasting and Portfolio Selection Through Machine Learning: An Application on BIST Participation 30 Index. Journal of Management and Economics Research. 2025;23(3):99-121. doi:10.11611/yead.1558158
Chicago
Gözkonan, Ümit Hasan, and Mahmut Karğın. 2025. “Stock Price Forecasting and Portfolio Selection Through Machine Learning: An Application on BIST Participation 30 Index”. Journal of Management and Economics Research 23 (3): 99-121. https://doi.org/10.11611/yead.1558158.
EndNote
Gözkonan ÜH, Karğın M (October 1, 2025) Stock Price Forecasting and Portfolio Selection Through Machine Learning: An Application on BIST Participation 30 Index. Journal of Management and Economics Research 23 3 99–121.
IEEE
[1]Ü. H. Gözkonan and M. Karğın, “Stock Price Forecasting and Portfolio Selection Through Machine Learning: An Application on BIST Participation 30 Index”, Journal of Management and Economics Research, vol. 23, no. 3, pp. 99–121, Oct. 2025, doi: 10.11611/yead.1558158.
ISNAD
Gözkonan, Ümit Hasan - Karğın, Mahmut. “Stock Price Forecasting and Portfolio Selection Through Machine Learning: An Application on BIST Participation 30 Index”. Journal of Management and Economics Research 23/3 (October 1, 2025): 99-121. https://doi.org/10.11611/yead.1558158.
JAMA
1.Gözkonan ÜH, Karğın M. Stock Price Forecasting and Portfolio Selection Through Machine Learning: An Application on BIST Participation 30 Index. Journal of Management and Economics Research. 2025;23:99–121.
MLA
Gözkonan, Ümit Hasan, and Mahmut Karğın. “Stock Price Forecasting and Portfolio Selection Through Machine Learning: An Application on BIST Participation 30 Index”. Journal of Management and Economics Research, vol. 23, no. 3, Oct. 2025, pp. 99-121, doi:10.11611/yead.1558158.
Vancouver
1.Ümit Hasan Gözkonan, Mahmut Karğın. Stock Price Forecasting and Portfolio Selection Through Machine Learning: An Application on BIST Participation 30 Index. Journal of Management and Economics Research. 2025 Oct. 1;23(3):99-121. doi:10.11611/yead.1558158