Check out the companies making headlines after the bell Monday:
Tesla Motors shares dipped slightly after a report that the SEC is investigating whether the automaker breached securities laws by failing to disclose a fatal crash in May involving an electric car in "Autopilot" mode. Tesla informed the National Highway Traffic Safety Administration, but it didn't disclose the crash, which took place on May 7, to investors until after it sold about $2 billion worth of stock in May.
Alcoa shares jumped in extended trading after the company reported its quarterly earnings and revenue, which beat analysts' expectations. The company posted adjusted second-quarter earnings per share of 15 cents on revenue of $5.3 billion. Analysts expected Alcoa to report earnings of about 9 cents per share on $5.2 billion in revenue, according to a consensus estimate from Thomson Reuters.
CEO and Chairman Klaus Kleinfeld highlighted the company's automotive sheet revenue hitting an all-time high and the performance of Alcoa's upstream segments.
Xerox shares popped after Bloomberg reported that the company is in talks to acquire R.R. Donnelley & Sons. The merger would add R.R. Donnelley to Xerox's copier, printer and related services business.
In January, Xerox announced its goal to "split into two publicly traded companies" by the end of 2016. Confidential sources told Bloomberg "a deal could be announced before Xerox's split."
United Airlines shares were choppy in after-hours trading. The company reported its operational performance for June 2016 stating that "consolidated traffic (revenue passenger miles) increased 1.4 percent and consolidated capacity (available seat miles) increased 0.5 percent versus June 2015."
While the company's consolidated passenger unit revenue slightly declined from June 2015, "the result was near the top end of the initial guidance range due to better international yields than originally expected and an increase in business travel in the final week of June, likely associated with the timing of the Fourth of July holiday," United said in a statement.
Seagate Technology shares soared after it announced preliminary financials for its fiscal fourth quarter and year-end 2016, which ended on July 1.
"Seagate expects to report revenue of approximately $2.65 billion" for the fiscal fourth quarter 2016, compared to previous revenue forecast "of approximately $2.3 billion." CEO and Chairman Steve Luczo believes the "long-term trend of exabyte storage demand growth" will drive revenue expectations.
— CNBC's Anita Balakrishnan and Everett Rosenfeld contributed to this report.