How much did the five biggest academic #publishers make in article processing charges (#APCs) 2015--2018?
https://doi.org/10.1162/qss_a_00272

"We estimate that globally authors paid $1.06 billion in publication fees to these publishers from 2015–2018."

That breaks down to $448.3m for APCs at #hybrid journals and $612.5m for APCs at full (non-hybrid) OA journals.

Here's the breakdown by publisher: Springer-Nature ($589.7m), Elsevier ($221.4m), Wiley ($114.3m), Taylor & Francis ($76.8m), Sage ($31.6m).

The Oligopoly’s Shift to Open Access. How the Big Five Academic Publishers Profit from Article Processing Charges

Abstract. This study aims to estimate the total amount of article processing charges (APCs) paid to publish open access (OA) in journals controlled by the five large commercial publishers Elsevier, Sage, Springer-Nature, Taylor & Francis and Wiley between 2015 and 2018. Using publication data from WoS, OA status from Unpaywall and annual APC prices from open datasets and historical fees retrieved via the Internet Archive Wayback Machine, we estimate that globally authors paid $1.06 billion in publication fees to these publishers from 2015–2018. Revenue from gold OA amounted to $612.5 million, while $448.3 million was obtained for publishing OA in hybrid journals. Among the five publishers, Springer-Nature made the most revenue from OA ($589.7 million), followed by Elsevier ($221.4 million), Wiley ($114.3 million), Taylor & Francis ($76.8 million) and Sage ($31.6 million). With Elsevier and Wiley making most of APC revenue from hybrid fees and others focusing on gold, different OA strategies could be observed between publishers.Peer Review. https://www.webofscience.com/api/gateway/wos/peer-review/10.1162/qss_a_00272

MIT Press
@petersuber Three years of hosting PDFs cost the same than putting two rovers on Mars.
https://www.planetary.org/space-policy/cost-of-the-mars-exploration-rovers
Cost of the Mars Exploration Rovers

The total cost of the Mars Exploration Rovers program was $1.08 billion. But that's not the whole story.

The Planetary Society
@petersuber Given that MDPI *alone* had $648M in possible APC revenues in 2022, things have gotten much worse--even without "hybrids."
@waltcrawford
It would be interesting to compare the "big 5" publishers by articles published with the "big 5" by APC revenue.