A federal appeals court panel on Friday upheld the federal government’s seizure of more than $75 million in overseas assets from the founders of Megaupload Ltd., a now-defunct file-sharing site accused of massive copyright infringement.

Owner Kim Dotcom and others involved in Megaupload challenged the seizure and the government’s insistence that they could not even try to reclaim their assets because of a federal law limiting appeals by foreign fugitives.