We are in a new era for mergers & acquisitions with companies fighting global regulatory overreach by not giving up and terminating deals when regulators attempt to block them. Companies and funds like Microsoft, JetBlue, TD, Standard General and Intercontinental Exchange have dug in and appealed decisions by regulators, provided various concessions, spun off units and extended closing dates to keep their mergers alive.
Unfortunately this means longer closing times and a great deal of uncertainty for arbitrageurs.