Gun share prices rise after mass shootings with the perception that tighter gun control rules will follow and that people need to better protect themselves.
Adding to uncertainty this week will be the rebalancing of Russell indexes, requiring fund managers to rebalance their own portfolios.
Fears of a China-led global slowdown, along with oil's steep slide, have dampened the market's expectations for a hike.
Global stocks plunged on Monday, with the Dow making its worst start to a year since 2008.
The Dow Jones industrial average rose 1.47 percent to 16,284.7.
The Nasdaq composite and S&P 500 both dropped more than 2 percent.
Major indexes fell almost 3 percent.
China's manufacturing sector shrank at its fastest pace in three years.
The Dow Jones industrial average rose 312.94 points to 15,979.38.
Traders now see a 24-percent chance that the Federal Reserve will increase rates in September.
China's market gyrations have stoked fears among global investors about the broader health of the Chinese economy.
Apple fell 6.2 percent, Microsoft lost 3.5 and Yahoo shed 2.2 percent.
The market suspended trading in all symbols.
A cyber espionage ring attacked more than 100 firms, most of them pharmaceutical and healthcare companies, to get insider information.
The current bull market still has a long way to go before it approaches the longest bull market in U.S. history, both in terms of duration and magnitude
Sales of the iPhone 6 and 6 Plus helped Apple chalk up a 12.2 percent jump in revenue last quarter
The data suggests the economy remained on solid ground, with the labor market gaining steam.
"This is the biggest IPO the world has ever seen, so there’s a celebratory mood on the floor, whether you like it or not."
The California-based maker of luxury electric cars said it lost $61.9 million, or 50 cents a share