Dozens of supporters were outside court as the man accused of fatally shooting the chief executive of UnitedHealthcare made his first appearance.
Luigi Mangione has pleaded not guilty to multiple counts of murder following the 4 December killing of Brian Thompson, 50, outside a midtown Manhattan hotel.
The 26-year-old is accused of ambushing and shooting the executive as he walked to an investor conference.
Dozens of people who showed up in court to support the suspect including former army intelligence analyst Chelsea Manning who was jailed for stealing classified diplomatic cables.
Dozens more queued in the hallway.
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Mangione is also facing federal charges that could carry the possibility of the death penalty.
The judge set a deadline of 9 April to submit pre-trial motions.
In addition to the New York cases, Mr Mangione also faces charges of forgery, carrying firearms without a licence, and other counts in Pennsylvania, where authorities arrested him at a McDonald’s.
Police say he was in possession of a gun, bullets, multiple fake IDs and a handwritten document that expressed “ill will” towards corporate America.
He is being held in a Brooklyn jail alongside several other high-profile defendants, including music mogul and rapper Sean “Diddy” Combs, and disgraced crypto entrepreneur Sam Bankman-Fried.
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The killing prompted some to voice their resentment at US health insurers, with Mangione attracting a cult following.
A poll taken in the wake of the shooting showed most Americans believe health insurance profits and coverage denials were partly to blame for the incident.
