v2026.1CASRAI Dictionary 714 entries across 20 domains · CC-BY 4.0714 entries · CC-BY 4.0

Dictionary termTrack EStablev2026.2

Subscribe-to-Open (S2O)

A business model in which a journal flips to open access for a given year if enough institutional subscribers renew their subscriptions, with the same subscription price funding open publication instead of access control.

ByCASRAI Editorial Board

· Last updated 21 May 2026

Examples

Worked examples

Is an instance
A journal achieves its S2O renewal threshold and opens the year's volume to all readers.
Is an instance
Library consortium members renew the journal in solidarity to support its diamond-equivalent OA model.

Counter-examples

Looks similar, but isn't

Not an instance
Marketing a journal as S2O but charging an APC if the threshold is missed.
Not an instance
Withdrawing institutional support, free-riding on other libraries' renewals.

Editorial commentary

Subscribe-to-Open (S2O) was developed by Annual Reviews and Berghahn Books and has been adopted by EDP Sciences, IWA Publishing and others. Each year, the publisher sets a renewal threshold; if reached, the entire content of that volume is published access" class="text-primary underline-offset-2 hover:underline" data-autolinked="true" title="Open access — CASRAI Dictionary">open access. If the threshold is missed, the volume reverts to closed access. The model avoids author-side APCs and the equity issues they raise, preserves the workflow of subscription procurement and is approved as a route to Plan S compliance. It depends on a free-rider problem being mitigated by community norms and short subscription suspension windows.

References

Annual Reviews S2O documentation. Crow R, Gallagher J, Naim K 'Subscribe to Open: A practical approach to flipping subscription journals' Learned Publishing 2020.

Also known as

S2O

Machine-readable encodings

Use in your systems

JATS XML <role> element

xml

<role vocab="credit"
      vocab-identifier="https://casrai.org/dictionary/"
      vocab-term="Subscribe-to-Open (S2O)"
      vocab-term-identifier="https://casrai.org/dictionary/term/subscribe-to-open" />

Schema.org DefinedTerm (JSON-LD)

json

{
  "@context": "https://schema.org",
  "@type": "DefinedTerm",
  "name": "Subscribe-to-Open (S2O)",
  "identifier": "https://casrai.org/dictionary/term/subscribe-to-open",
  "description": "A business model in which a journal flips to open access for a given year if enough institutional subscribers renew their subscriptions, with the same subscription price funding open publication instead of access control.",
  "inDefinedTermSet": "https://casrai.org/dictionary/domain/knowledge-equity-diversity-global-south-inclusion/",
  "url": "https://casrai.org/dictionary/term/subscribe-to-open",
  "sameAs": [
    "S2O"
  ],
  "license": "https://creativecommons.org/licenses/by/4.0/"
}

Adopted by research universities worldwide

View CASRAI adoption →