Gannett's Tucson Citizen will close March 21, which could help Lee's Arizona Daily Star. The two papers have been in a joint operating agreement since 1940, and have split costs and profits 50-50. (The Star is the bigger of the two papers.) That JOA continues through 2015, meaning Gannett will share the costs and profits until then.
The St. Louis Post-Dispatch recently got out of its JOA with the St. Louis Globe-Democrat, which closed in 1986.