Check out the companies making headlines before the bell. Shockwave Medical — The medical device stock rose 1.6% after Johnson & Johnson announced it would buy the company for $12.5 billion. The transaction would boost J & J’s portfolio of cardiovascular disease treatment devices. Krispy Kreme — Shares of the doughnut chain surged 5% in premarket trading after Piper Sandler upgraded the stock to overweight from neutral. The Wall Street firm said Krispy Kreme is on the verge of a major growth move after brokering a nationwide partnership with McDonald’s last week. It called the partnership “a game changer” for the business. Cinemark — Shares of the movie theater chain popped nearly 5% following a double upgrade to overweight from underweight at Wells Fargo. Analyst Omar Mejias pointed to rising demand, better performance and an overall positive backdrop for the movie industry as catalysts. Altice USA — The stock dropped nearly 6% after Wells Fargo downgraded the cable television firm to underweight from equal weight. The bank is now skeptical on Altice’s M & A prospects, analyst Steven Cahall wrote. Ollie’s — Shares added more than 2% after Loop Capital upgraded the bargain retailer to buy from hold. The firm cited its relatively cheap valuation compared to its peers and its store base expansion potential. Public Storage — The self storage stock moved up nearly 1% after Wells Fargo upgraded its rating for the company to overweight from equal weight. The bank listed the stock as its “top idea in storage,” citing “industry-leading growth metrics” and its strong footing to navigate an uncertain housing environment. Scotts Miracle-Gro — The maker of lawn and garden-care products slipped 0.8% following a downgrade by Truist to hold from buy. The firm said much of the near-term good news is now priced into the stock and sees limited catalysts on the horizon for a move higher. Fox Corporation Class A — The stock rose 1% following an upgrade to buy from neutral at Seaport Research. As reasons for the upgrade, the investment firm cited cyclically strong ad spending, Fox’s growing Tubi service, solid ratings momentum and the company’s healthy balance sheet. Western Digital — The semiconductor stock rose nearly 3.5% after an upgrade to buy from neutral by Rosenblatt Securities. Western Digital should benefit from a broad rise in prices for a key type of memory chip, Rosenblatt said. Snowflake — Shares gained 1.4% after Rosenblatt Securities upgraded the cloud computing company to buy from neutral, citing healthy customer interest in the platform. Agilent Technologies — The life sciences applications company rose more than 1% after receiving an upgrade to buy from hold at Stifel. Analyst Daniel Arias believes that good instrument demand and an attractive valuation will make the stock more compelling to investors. — CNBC’s Michelle Fox, Hakyung Kim, Yun Li, Sarah Min and Jesse Pound contributed reporting.