{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T01:01:11Z","timestamp":1760058071789,"version":"build-2065373602"},"reference-count":33,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2025,3,18]],"date-time":"2025-03-18T00:00:00Z","timestamp":1742256000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003725","name":"Ministry of Education, Korea","doi-asserted-by":"publisher","award":["2022R1I1A3070919"],"award-info":[{"award-number":["2022R1I1A3070919"]}],"id":[{"id":"10.13039\/501100003725","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Systems"],"abstract":"<jats:p>Increasing supply chain uncertainty due to market volatility has heightened the need for more flexible procurement strategies. While procurement through long-term forward contracts provides supply stability and cost predictability, it limits adaptability. Option contracts offer procurement flexibility, but require additional upfront premiums. Meanwhile, the spot market enables real-time purchasing without prior commitments, enhancing flexibility but exposing buyers to price volatility. Despite the growing adoption of portfolio procurement\u2014combining forward contracts, option contracts, and spot market purchases\u2014the existing research primarily examines these channels in isolation or in limited combinations, lacking an integrated perspective. This study addresses this gap by developing a comprehensive procurement model that simultaneously optimizes procurement decisions across all three channels under uncertain demand and fluctuating spot prices. Unlike prior studies, which often analyze one or two procurement channels separately, our model presents a novel, holistic framework that balances cost efficiency, risk mitigation, and adaptability. Our findings demonstrate that incorporating the spot market significantly enhances procurement flexibility and profitability, particularly in environments with high demand uncertainty and price volatility. Additionally, sensitivity analysis reveals how fluctuations in spot prices and demand uncertainty influence optimal procurement decisions. By introducing a new, practical approach to portfolio procurement, this study provides managerial insights that help businesses navigate complex and uncertain supply chain environments more effectively. However, this study assumes unlimited spot market capacity and reliable suppliers, highlighting a limitation that future research should address.<\/jats:p>","DOI":"10.3390\/systems13030210","type":"journal-article","created":{"date-parts":[[2025,3,18]],"date-time":"2025-03-18T12:03:06Z","timestamp":1742299386000},"page":"210","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Portfolio Procurement Strategies with Forward and Option Contracts Combined with Spot Market"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0009-0000-0836-8625","authenticated-orcid":false,"given":"Nurul Anastasya","family":"Talaba","sequence":"first","affiliation":[{"name":"Department of Industrial and Data Science Engineering, Pukyong National University, Busan 48513, Republic of Korea"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1695-3039","authenticated-orcid":false,"given":"Pyung-Hoi","family":"Koo","sequence":"additional","affiliation":[{"name":"Department of System Management and Safety Engineering, Pukyong National University, Busan 48513, Republic of Korea"}]}],"member":"1968","published-online":{"date-parts":[[2025,3,18]]},"reference":[{"key":"ref_1","first-page":"129","article-title":"Supply chain incentive alignment: The gap between perceived importance and actual practice","volume":"12","author":"Norrman","year":"2019","journal-title":"Oper. 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