Check out the companies making headlines after the bell:

Costco shares fell 3 percent after the market close after reporting disappointing quarterly earnings and revenue. The company reported $34.31 billion in revenue, falling short of the $34.79 billion estimated by analysts polled by Refinitiv. The company posted adjusted earnings of $1.61 per share, just shy of the $1.62 expected by analysts.

Starbucks shares fell more than 3 percent after hours after announcing a new delivery service. The coffee chain will partner with food delivery service Uber Eats at 2,000 of its stores in the U.S. beginning in 2019. The company tested this in Miami in September.

Alliant Energy slipped 2 percent after-hours as the company announced a slate of executive changes, including a new president and chief operating officer and two new senior vice presidents. John Larsen will be the new president and COO after former president Douglas Kopp retires in 2019.