Midday movers: Roku, Southwest Airlines, Moderna and more

© Reuters.

Investing.com -- U.S. stocks were falling on Wednesday, as higher oil prices and weak global economic data weighed on sentiment.

Here are some of the biggest U.S. stock movers today:

• Roku (NASDAQ:ROKU) stock rose 3.3% after the video streaming company said it will reduce its workforce by about 10% and limit new hiring to lower expenses.

• Tellurian (NYSE:TELL) stock rose 5.7% after the oil and gas company signed a supply agreement with Baker Hughes, up 0.4%, for its U.S. liquefied natural gas export project.

• Gitlab (NASDAQ:GTLB) stock rose 0.9% after the software coding platform posted a surprise profit for the second quarter.

• Alaska Air (NYSE:ALK) stock fell 0.4% after cutting its pretax margin forecast for the third quarter, while Southwest Airlines (NYSE:LUV) stock fell 2.8% and United Airlines (NASDAQ:UAL) stock fell 0.1% after the carriers warned of higher fuel costs due to a jump in crude prices.

• Moderna (NASDAQ:MRNA) stock fell 2.3% after it said the clinical trial data showed its updated COVID-19 vaccine will likely be effective against the highly-mutated BA.2.86 subvariant of the coronavirus.

• Telefonica (BME:TEF) (NYSE:TEF) ADRs fell 3.9% after the Spanish government said it is analysing Saudi Arabian group STC's purchase of a 9.9% stake in the telecoms giant to ensure its strategic interests are defended.

• Block (NYSE:SQ) stock fell 1.1% after UBS downgraded its stance on the fintech company to ‘neutral’ from ‘buy’, saying its gross profit growth will likely decelerate in the second half of 2023 and throughout next year due to a softening in consumer discretionary spending,

• Toast (NYSE:TOST) stock fell 1.4% after UBS upgraded the restaurant management software company to ‘buy’ from ‘neutral’, saying it can rally nearly 40%.

• Stem (NYSE:STEM) stock fell 7.9% after Morgan Stanley (NYSE:MS) downgraded the energy storage company to ‘equal weight’ from ‘overweight’, expressing concerns about the company's ability to reach its targets.