...Fitch Ratings' upgrade of Harbour Energy PLC's Long-Term Issuer Default Rating (IDR) and senior unsecured rating to `BBB-' from `BB'/Rating Watch Positive in September 2024 followed the completion of Harbour's acquisition of substantially all of Wintershall Dea AG's upstream assets. The senior unsecured rating of the notes issued by Wintershall Dea Finance B.V. was downgraded to `BBB-' from `BBB' and the subordinated rating for hybrid notes issued by Wintershall Dea Finance 2 B.V. to `BB' from `BB+'. The issuers became Harbour's subsidiaries, and the guarantor was switched to Harbour Energy PLC on closing of the Business Combination Agreement. The upgrade reflects Harbour's enlarged size, improved geographical and asset diversification and higher reserves post-acquisition. However, reserve life and production costs remain weaker than peers. This is counterbalanced by moderate financial leverage and strong cash flow with stable production....