EDP Sciences and SMAI have published the fifth annual Transparency Report for their Subscribe to Open (S2O) mathematics programme, providing an open account of how the programme is funded, how publication costs are distributed and how the journals are progressing towards long-term financial sustainability. 

The publication of the report comes shortly after confirmation that the remaining two journals in the programme, ESAIM: Control, Optimisation and Calculus of Variations and ESAIM: Mathematical Modelling and Numerical Analysis will also publish in open access in 2026. This follows additional support from CNRS, allowing all six journals in the portfolio to remain freely available to readers without article processing charges for authors in 2026.

The annual Transparency Report has become a central part of the programme since its launch in 2021. Published each year, it provides libraries, funders and the wider mathematics community with detailed information on subscription renewals, publication activity, costs, revenue and governance. 

The 2025 report shows that:

• All six journals have published continuously in open access for five consecutive years (Mathematical Modelling of Natural Phenomena for six years);
• In 2025, the journals published 456 articles and more than 12,200 pages;
• The estimated average publication cost fell from around €950 per article in 2024 to around €800 in 2025;
• Revenue covered 76.1% of publication costs, compared with 71.0% in 2024;
• Data and code sharing continued to grow, with the number of articles reporting deposits in public repositories tripling from 15 in 2023 to 45 in 2025;
• Authors continued to publish without APCs.  

The report also provides a detailed breakdown of where publication costs are incurred, from editorial office support and production through to digital infrastructure, marketing and long-term preservation. It highlights that library subscriptions remain the largest source of funding, while complementary support continues to play an important role in helping the programme move closer to financial sustainability.  

“Transparency has always been one of the principles behind our Subscribe to Open programme. By publishing these reports each year, we want libraries, authors and funders to understand how the programme works, what it costs to run, and how their continued support contributes to equitable open access.” said Selina La Barbera, Editorial Director at EDP Sciences.

Nicolas Forcadel, Director of Publications at SMAI, said: “As a learned society, SMAI’s priority is to support the communication of high-quality mathematics. Subscribe to Open enables us to do that without shifting publication costs onto authors. The annual Transparency Report reflects the same philosophy by giving our community a clear view of how the model is funded and how it continues to evolve.”

The confirmation that all six journals will publish in open access in 2026 demonstrates the strength of support from the mathematics community. While library subscriptions remain the foundation of the model, additional support from organisations including CNRS helps ensure that open access can be maintained without transferring publication costs to authors.

The report also notes encouraging progress in other areas, including increased sharing of research data and code across the portfolio, reflecting the programme’s broader commitment to Open Science. 

The full 2025 Transparency Report and a new summary version are now available on the EDP Sciences website.