Short answers, pulled from the story.
Marvel Entertainment was active from the 2nd of June 1998, when it formed from the merger of Marvel Entertainment Group and Toy Biz, until the 29th of March 2023, when its remaining units were folded into Disney's other divisions.
On the 6th of January 1989, Ronald Perelman's MacAndrews & Forbes Holdings bought Marvel from New World Entertainment for $82.5 million. The deal excluded Marvel Productions, which remained with New World's television and movie business.
Marvel filed for Chapter 11 bankruptcy protection on the 27th of December 1996 after reporting its first annual loss in late 1995 and laying off 275 employees in January 1996. Losses were driven by a costly direct distribution push, a collapsing comic book market, a 1994 Major League Baseball strike that hurt its Fleer card unit, and weak Disney box office results that hurt its Panini sticker business.
Disney announced on the 31st of August 2009 that it would acquire Marvel Entertainment for $4 billion, offering shareholders $30 in cash plus about 0.745 Disney shares per Marvel share. Shareholders approved the deal on the 31st of December 2009, and it closed that same day.
Los Angeles patent attorney Carole E. Handler found a loophole in how the Marvel name had been licensed and used it to reclaim Marvel Enterprises' movie rights to Spider-Man. This followed Toy Biz hiring an attorney to review the company's licensing agreements after the 1998 bankruptcy reorganization.
Disney laid off Marvel Entertainment chairman Isaac Perlmutter on the 29th of March 2023, the same day the subsidiary's remaining units were folded into Disney's other divisions. Perlmutter had served as chairman since the 1st of January 2017, after an earlier stint running Marvel in the 1990s.