What does Tier 2 coordinated preservation cost, and what conditions make it sustainable?

A subsidiary question under Q-0004. Tier 2 fees are documented and modest (CLOCKSS $550-$18K, LOCKSS $2.6-$13K, HathiTrust $6.6-$13K, APTrust $20K + $420/TB, Portico $1.5-$25K). The question is not whether the fees are affordable but whether the consortium model behind them is durable.

The answer is C-0030 (and structurally C-0012). Proportional fees, easy ingestion, and automated contribution produce consortia that survive — CLOCKSS for 20 years, LOCKSS for 27, HathiTrust for 18. Flat fees, difficult ingestion, and voluntary contribution produce consortia that don't — DPN charged $20K/year flat regardless of size and shut down in 2018 with 27 of ~60 members ever depositing content; MetaArchive dissolved in 2025 after fiscal-host requirements changed and reserves fell below threshold.

The economic risk at Tier 2 lives in the organizational sustainability conditions, not the headline fee. The consortia that last are the ones in which participation is rational at the institutional level.