Check out the companies making headlines before the bell:

Big Lots – The discount retailer reported adjusted quarterly earnings of 92 cents per share, compared to a consensus estimate of 70 cents a share. Revenue was slightly above forecasts, although comparable-store sales were up a less-than-expected 1.5%. Big Lots also raised its full-year profit forecast.

Genesco – The apparel and accessories retailer earned an adjusted 33 cents per share for its latest quarter, well above the consensus estimate of 4 cents a share. Revenue beat forecasts as well, and a comparable-store sales increase of 5% beat the 0.6% consensus of analysts polled by Refinitiv.

Ford Motor, General Motors – These and other auto stocks are falling this morning following President Donald Trump's threat to impose tariffs on Mexican imports. GM is the largest automaker in Mexico with 14 plants, among the companies taking advantage of proximity to the U.S. border and lower labor costs.

Uber Technologies — Uber posted a loss of $1.01 billion in its first quarter as a public company, matching Wall Street's forecasts. Revenue was slightly above expectations and up 20% over a year earlier.

Gap Inc. – Gap earned an adjusted 24 cents per share for its latest quarter, 8 cents a share below consensus forecasts. The apparel retailer's revenue was also below forecasts, and a same store sales decline of 4% was larger than the 1.2% drop that analysts had been expecting. The same-store sales decline was most prominent at the Gap flagship brand.

Costco – Costco beat estimates by 7 cents a share, with adjusted quarterly profit of $1.89 per share. The warehouse retailer's revenue was also above forecasts. Comparable-store sales rose 5.5%, just under the consensus forecast for a 5.6% increase.

Ulta Beauty – Ulta reported quarterly profit of $3.26 per share, compared to a consensus estimate of $3.07 a share. The cosmetics retailer's revenue was slightly below forecasts, with comparable-store sales in line with estimates. Ulta also raised its full-year guidance.

Williams-Sonoma – Williams-Sonoma came in 12 cents a share above estimates, with quarterly earnings of 81 cents per share. The housewares retailer's revenue matched Street forecasts. Comparable-store sales were up 3.5%, more than double the 1.7% consensus estimate. Williams-Sonoma also raised its full-year earnings outlook.

Dell Technologies – Dell reported adjusted quarterly earnings of $1.45 per share, 24 cents a share above estimates. The computer maker's revenue came in below forecasts on slowing demand in China.

Amazon.com – Amazon is interested in buying Boost Mobile from T-Mobile US and Sprint, according to Reuters. T-Mobile and Sprint are planning to sell the prepaid mobile brand in order to get their planned merger approved by regulators.

Okta – Okta reported an adjusted quarterly loss of 19 cents per share, 2 cents a share smaller than Wall Street had expected. The maker of identity management software also saw better-than-expected revenue during the quarter, as subscription revenue grew 52% compared to a year earlier.

Kraft Heinz – Piper Jaffray upgraded the food maker's stock to "neutral" from "underweight," saying caution about the company's outlook is reflected in its current valuation. The stock has lost more than half its value over the past year.