Via the Quantum Pontiff, news that the Simons Foundation will be providing up to \$300,000 in financial support to the arXiv for each of the next five year. Last year, the arXiv announced a \$60K planning grant from Simons. Now the Foundation is stepping in with a much bigger contributions, for details see here.
This kind of support for open-access publication is an excellent way for Simons to use its resources. Perhaps this will be the beginning of a larger effort to buy back control of the math and physics literature from commercial publishers and set up a viable model for making this literature available to all going forward. This may be an expensive undertaking, but Simons (and other math/physics-friendly financiers) have resources on the scale necessary to do this.