General Electric jumped 4 percent Monday after activist investor Nelson Pelts bought a stake in the company.
Twitter rose 5 percent after a long-running search for a full-time CEO concluded. Co-founder Jack Dorsey will have a second chance at leading the company.
The Dow Jones industrial average gained 188 points, or 1.1 percent, to 16,662 as of 11:45 a.m. Eastern time.