Shares of Pharmacy-benefit managers (PBMs) including CVS Health Corp (NYSE:CVS), UnitedHealth Group Inc (NYSE:UNH) and Cigna Group (NYSE:CI) are moving lower Tuesday on continued downside pressure following aggressive commentary from President-elect Donald Trump regarding plans to cut drug middlemen out of the industry.

What To Know: Trump on Monday announced plans to "knock out" PBMs, or so-called drug middlemen, from the healthcare industry, according to Bloomberg.

"You know the middleman, right? The horrible middleman that makes more money frankly than the drug companies, and they don't do anything except they're a middleman," President-elect Trump said. "We're going to knock out the middleman."

CVS Health's Caremark, UnitedHealth's OptumRx and Cigna's Express Scripts are the three largest PBMs. The companies have faced repeated criticism for driving up the prices of drugs. The role of PBMs in the industry has seen increased attention in recent weeks following the murder of UnitedHealthcare CEO Brian Thompson.

Shares of CVS, UnitedHealth and Cigna all traded lower on Monday following Trump's comments. The trio is moving lower again on Tuesday after Pfizer Inc (NYSE:PFE) CEO Albert Bourla said Trump is "very committed" to implementing changes to stop drug middlemen from inflating prices.

"The president has very strong views," Bourla said on a call with analysts and investors Tuesday morning, before adding that Trump "wants transparency."

"It seems to me that he is very committed to make this happen," the Pfizer CEO said.

Sen. Elizabeth Warren (D.-Mass.) and Sen. Josh Hawley (R.-Mo.) unveiled a new Senate bill last week that would require the companies that own PBMs to divest those businesses within three years.

The proposed legislation is not expected to gain traction in Congress until next year.

CVS, UNH CI Price Action: At the time of publication, CVS shares were down 5.48% at $44.01, UnitedHealth shares were down 2.66% at $485.15 and Cigna shares were down 2.84% at $265.54, according to Benzinga Pro.