Shares of Comcast dove nearly 7 percent Thursday afternoon after one executive said investors should expect the company to expect a large subscriber loss during the third quarter.

It’s the biggest dive in six years, since August 8, 2011.

Comcast executive vice president Matthew Strauss said during a Merrill Lynch media conference that the company expects to report a loss of 100,000 to 150,000 subscribers during the third quarter, CNBC’s Julia Boorstin said on “Power Lunch.”

Strauss blamed competition and Hurricane Harvey for the losses and said it’s the “most competitive quarter” in recent history. Comcast is still expected to hit its other numbers.

Traditional cable networks, including Comcast, have had to fight to keep customers as streaming TV services, which provide a selection of “skinny bundles” at more affordable prices than some cable packages, become more popular.

Disclosure: Comcast is the owner of NBCUniversal, the parent company of CNBC and CNBC.com.