Netflix, which announced layoff plans last week, posted a third-quarter profit above Wall Street's expectations, but investors sent shares down after the streaming company lowered its ad sales guidance, prompting worries about slowing revenue growth.

Netflix said Tuesday it earned $3. 66 billion, or 87 cents per share, for the July-September period.

That's up 44% from $2. 55 billion, or 59 cents per share, a year earlier.