Leaked documents are alleging that the Intertribal Council of Nevada, a nonprofit organization, overdrew $1.6 million from a National Telecommunications and Information Administration grant.
The marketplace itself has also evolved in recent years, with more insurers joining.
If there isn't a winner, the jackpot will inch closer to the record $2.04 billion Powerball prize won last November.
The estimated $1.1 billion jackpot has been growing for more than two months.
With no winner, the jackpot goes up to an estimated $1.1 billion for a drawing Tuesday night.
The new jackpot will remain the sixth-largest jackpot in U.S. history.
The jackpot is the largest since a $2.04 billion Powerball prize was won Nov. 8 in California.
The next drawing will be Friday night.
The current $565 million Mega Millions jackpot has been building since Oct. 14.
It's the second-largest Mega Millions Jackpot ever.