Check out the companies making headlines in midday trading.

Oil stocks — Petroleum refiners Valero Energy and Marathon Petroleum gained 1.4% and 1.5%, respectively, as West Texas Intermediate and Brent crude prices reached their highest levels since November, 2022. The oil services ETF and S&P 500 Energy Index both rose 1%.

Arm Holdings — Shares declined 7.4% on the back of the company’s blockbuster Nasdaq debut Thursday, when it surged nearly 25%. Bernstein initiated coverage of the chip designer with an underperform rating on Monday, saying it’s “too early” to name Arm an AI winner. Needham initiated coverage of the chip designer with a hold rating on Friday, saying Arm’s valuation looks “full” in a post-smartphone era.

Moderna — The pharmaceutical company lost more than 8% Monday, making it the biggest decliner in the S&P 500. Co-founder and board chairman Noubar Afeyan sold 15,000 shares for approximately $1.64 million, according to a Securities and Exchange Commission filing. Pharmaceutical peer Pfizer said in a press conference Monday that it expects a 24% vaccination rate for Covid-19 shots in the U.S. this year. Moderna’s updated Covid vaccines have been approved in both the U.S. and the U.K.  

Tesla — Shares of the electric vehicle maker slipped 3% after Goldman Sachs lowered its earnings estimate. Analyst Mark Delaney cited the potential for further price cuts and lower margins as reasons for the reduction.

PayPal — The payment platform slipped 1.5% following a downgrade to market perform from outperform by MoffetNathanson. The firm said PayP still faces challenges as a new CEO takes the helm.

Ralph Lauren — The luxury retailer saw its shares rise 0.7% after Guggenheim upgraded the stock to buy from neutral. The Wall Street firm said Ralph Lauren’s earnings are set to benefit from several cyclical tailwinds, including clean inventories, lower freight expenses and lower cotton cost, adding that the recent pullback has provided an attractive entry point.

Enphase Energy — Shares lost 2.6% after Citi lowered its price target on shares to $170 from $209 while keeping its buy rating. The new price target implies 41% upside from Friday’s close.

Tenable Holdings — Shares gained 2.6% after TD Cowen initiated coverage of the cybersecurity stock with an outperform rating. Cowen said Tenable appears well positioned to benefit from tailwinds in a total addressable market of $25 billion.

Vertex — Shares of the tax software stock climbed 2.4% Monday. Morgan Stanley resumed coverage of Vertex on Monday with an overweight rating. Analyst Chris Quintero highlighted the growth opportunity for the company following a strong investment cycle.

DoorDash — Shares of the food delivery service ended flat Monday, after adding as much as 1.6% midday. Mizuho upgraded the company to buy from neutral in a Monday note, citing continued market share gains.The company also expanded its partnership with Aldi to allow alcohol orders, in addition to adding new grocery providers, including Lowe’s Markets and Eataly.

Micron Technology — The stock gained 0.9% after Deutsche Bank upgraded the memory and storage semiconductor maker to buy from hold on Sunday, and also raised its target price. The firm said Micron’s pricing power in direct random access memory is hitting an inflection point, and could push the company to beat expectations for its fiscal first-quarter revenue and earnings guidance in November.

Paramount Global — Shares of the entertainment company fell 3.2% Monday. Raymond James began research coverage with a market perform rating, while giving peers Disney and Warner Bros Discovery outperform ratings.

Simply Good Foods — Shares of the food and beverage company added 3.6% following a Morgan Stanley upgrade to overweight from equal-weight on Monday. The investment bank bumped up the stock’s price target to $40 from $37, citing Simply Good Foods’ diverse product offering and shifting consumer preferences to healthier choices as catalysts.

Iridium Communications – The satellite company’s stock jumped more than 5% following an upgrade from Deutsche Bank to buy from hold. The firm said it sees an attractive entry point for Iridium shares, which have plunged 19.4% quarter to date. 

ASGN — Shares of the digital innovations solutions company rallied nearly 3% Monday. Wells Fargo started research coverage with an overweight rating on the company, encouraging investors to buy the dip. The stock is little changed in 2023.

— CNBC’s Alex Harring, Brian Evans, Samantha Subin, Yun Li, Lisa Kailai Han, Pia Singh and Michelle Fox contributed reporting