Check out the companies making headlines in the premarket Monday:

Twitter (TWTR) — Elliott Management founder Paul Singer is looking to replace Twitter CEO Jack Dorsey, noting the company’s top executive’s focus is split by also running Square (SQ), CNBC has learned through a source. Twitter shares were up 5.4%.

Apple (AAPL) — An analyst at Oppenheimer upgraded the tech giant to “outperform” from “perform,” noting Apple “has mastered the art to turn technology into deeply personal and indispensable everyday objects from phones to Watch to AirPods.” The analyst added that given the company’s “products and services will prove more resilient than competitive products in uncertain times.”

General Electric (GE) — JPMorgan analyst Stephen Tusa, who had a longtime bearish stance on GE, upgraded the industrial giant to “neutral” from “underweight,” noting the company’s floor on free cash flow exceeded his expectations. “We were wrong,” Tusa said in a note to clients.

Verizon (VZ) — Verizon was upgraded to “outperform” from “market perform” by an analyst at Cowen. “We look to take advantage of the recent sell-off with the stock now trading at a dividend spread (vs. the 10-yr rate) not seen in 7+ years,” according to the analyst, who added there is low risk to Verizon’s earnings at this moment.

Western Digital (WDC), Micron (MU) — Western Digital and Micron were upgraded to “outperform” and “neutral,” respectively, by a Baird analyst. Memory chip “pricing positive outlooks remain unchanged for the year, despite current demand weakness in smartphones and PCs,” according to the analyst.

JPMorgan Chase (JPM) — A Piper Sandler analyst upgraded JPMorgan Chase to “overweight” from “neutral,” calling the stock a “relative winner in any macro-environment.” The analyst also said that after a “significant market selloff, we believe [JPMorgan] is poised to be a relative outperformer whether the operating environment continues to deteriorate or rebounds.”

Gilead Sciences (GILD) — Gilead Sciences announced it will buy immune-oncology company Forty Seven (FTSV) for $4.9 billion in cash, or $95.50 per share. The deal represents a premium of 64.7% to the stock’s closing price on Friday.

Carnival (CCL), American Airlines (AAL), Delta (DAL) — Travel stocks Carnival, Delta, and American Airlines all fell as the number of coronavirus cases around the world jumped over the weekend. In China, an additional 202 additional cases were reported. South Korea also confirmed another 123 cases.

SmileDirectClub (SDC) — A UBS analyst cut his SmileDirectClub rating to “neutral” from “buy,” and slashed his price target to $9 per share from $18 per share. “The company needs to show that it can sell its clear aligner products in a model that can generate profits and cash flow for the company and shareholders,” the analyst said. SmileDirectClub shares dipped 2.4% in the premarket.

—CNBC’s Michael Bloom contributed to this report.