Gambling Compliance said those states included California, Colorado, Hawaii and Pennsylvania.
In a research paper released Tuesday Feb. 4, the group said 2014 was shaping up to be a busy year for efforts to legalize online gambling.
Legislation in California is being hammered out that would allow online gambling by tribal casinos in the state.
Last year, three states legalized online gambling. Nevada in April was the first state, followed by New Jersey and Delaware in November.
Similar legislation at the federal level, however, seems unlikely, the group said.
