Last week, a DraftKings employee admitted to inadvertently releasing data before the start of the third week of N.F.L. games, a move akin to insider trading in the stock market. The employee — a midlevel content manager — won $350,000 at rival site FanDuel that same week.
. . .
A spokesman for DraftKings acknowledged that employees of both companies have won big jackpots playing at other daily fantasy sites. Late Monday, the two companies temporarily banned their employees from playing games or in tournaments at any other site; they already had prohibited their employees from playing on their own company sites.