Players wagered a total of $15.2m on sports across the two operators in March, marginally down from $15.3m in February.
William Hill, which has a retail facility at the Capital One Arena and runs a mobile sportsbook, available to players within two blocks of the venue, again led the market in March.
Players bet $11.4m with William Hill during the month, up 2.7% on February, winning $10.3m in the process. This left the bookmaker with $1.2m in gross gaming revenue, a month-on-month increase of 63.8%.
Gambet, operated by the DC Lottery and powered by Intralot, saw players place $3.8m in bets during March, down 9.5% from February.
However, as consumers won a total of $3.1m betting with Gambet, this resulted in $715,244 in gross gaming revenue, which was 19.2% higher than the previous month.