According to Odaily Planet Daily, the GMX hacker has sent an on-chain message to the GMX deployer address stating, "The funds will be returned later."
Previously, it was reported that GMX suffered a theft of assets worth $42 million, and GMX has left a message to the hacker's address offering a 10% white hat bounty.
Related reading: "Over $40 Million Stolen: The Full Story of the Precise Attack on GMX"