The community-driven fundraiser for the toddler was nearing $3 million as of early Thursday. Ackman, founder and CEO of Pershing Square Capital Management, donated under the name "William Ackman," his office confirmed to Fortune and Insider. His office didn't immediately respond to a request from USA TODAY.
Aiden’s parents, Kevin McCarthy, 37, and Irina McCarthy, 35, were among the seven people killed when a gunman opened fire from a rooftop on the Independence Day parade. A 21-year-old suspect, Robert Crimo III, is in custody.
In the aftermath of the tragedy, Ackman criticized the lack of action over mass shootings in the U.S. over Twitter: "There have been 309 mass shootings in the US YTD, an average of 12 per week, nearly two per day. The trend is not our friend."
$2 million raised: Highland Park rallied to help toddler after his parents were killed.
After the shooting, strangers found the boy and mobilized the community to find his family as neighbors shared his photo across social media with pleas to help identify him.
"The North Shore community rallied to help a boy who we knew nothing about," according to a verified GoFundMe page. "We took him to safety under tragic circumstances, came together to locate his grandparents, and prayed for the safety of his family.
"Aiden will be cared for by his loving family and he will have a long road ahead to heal, find stability, and ultimately navigate life as an orphan," the GoFundMe page added. "He is surrounded by a community of friends and extended family that will embrace him with love, and any means available to ensure he has everything he needs as he grows."
This article originally appeared on USA TODAY: Billionaire donates $18K to child who lost parents in Highland Park