Midday movers: Robinhood, KeyCorp stock rise; Hawaiian Electric falls

Investing.com -- U.S. stock futures were mixed Monday, in a calm trading at the start of the week that includes the release of the latest consumer prices data.

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

• Starbucks (NASDAQ:SBUX) stock rose 3.5% after the Wall Street Journal reported that activist investor Starboard Value has taken a stake in the coffee giant, and wants the company to take steps to improve its stock price.

• Pfizer (NYSE:PFE) (PFE) stock rose 0.3% after the drugs giant said its respiratory syncytial virus (RSV) vaccine Abrysvo generated a strong immune response in a late-stage study of adults with a compromised immune system.

• Hawaiian Electric (HE) stock slumped 15% after the utility firm raised "going concern" doubts late last week, in the wake of disclosing that it did not have a financing plan in place for the $1.99 billion Maui wildfire settlement it reached earlier this month.

• Robinhood (NASDAQ:HOOD) stock rose 2.6% after brokerage Piper Sandler upgraded its stance on the trading platform to ‘overweight’ from ‘neutral’, seeing the recent pullback as a buying opportunity.

• KeyCorp (NYSE:KEY) stock soared 12% after a minority investment by The Bank of Nova Scotia, with the deal valued at around $2.8 billion representing a 14.9% pro forma ownership in KeyCorp's common stock.

• Marathon Digital (NASDAQ:MARA) stock fell 8% after the cryptocurrency miner announced plans for a $250 million convertible debt offering.

• Trump Media&Technology (DJT) stock slipped 4% with Elon Musk set to interview Donald Trump Monday on the social media site X, a rival to the Republican presidential candidate’s own social media site Truth Social.