Governors from seven East Coast states formed a coalition on Monday, led by New York, to develop a joint reopening plan. Three governors from the West Coast formed a similar plan. The 10 states, mostly led by Democrats, together make up 38% of the U.S. economy. As part of Cuomo’s effort, McKinsey & Co. is producing models on testing, infections and other key data points that will underpin decisions on how and when to reopen the region’s economy, the sources said.