NEW YORK—With sports gambling now legal in more than 20 U.S. states, there also are new business opportunities, and potential pitfalls, for broadcasters and streaming services that seek to tie in betting content, or perhaps even market separately to the sports viewing and gambling audiences, according to a recent review of the market by eMarketer.

According to the firm’s review, sports gambling was legal and active in 21 states as well as the District of Columbia, as of May. An additional six states had legalized betting, but did not yet have live services, and 14 other states had active pre-filed legislation aimed at legalization. Only nine U.S. states had either no legislation or dead legislation as of May, according to eMarketer’s review.

A study by research and brokerage firm Gabelli Securities and the U.S. Census Bureau estimates that legalized sports gambling in the US will generate $2.1 billion in revenues this year and projects growth to $10.1 billion by 2028.

Other companies predict even higher revenues from legalized sports betting in the U.S., with Morgan Stanley estimating a market size of $15 billion by 2025 and Macquarie Research forecasting $30 billion by 2030.

Despite varying forecasts, which could result from differences in methodology, “the takeaway is that gambling will produce significant new revenues for sports rights holders, as well as opportunities to integrate this content with traditional broadcasts and streams,” eMarketer said.

In another sign of sports gambling’s momentum, the 19 regional sports networks owned by Sinclair Broadcast Group were rebranded to Bally’s in an agreement between the broadcaster and the casino operator. These initiatives notwithstanding, some experts are cautious about the nexus between sports and gambling.

“Gambling in general is a sensitive topic for brands and advertisers,” said JoAnna Foyle, senior vice president of inventory partnerships at The Trade Desk. “Regardless of legality, it's just not typically a place that some of the more conservative brands want to be. That’s not to say there won't be participation or that gambling won’t attract more advertisers, but at least with the biggest brands, there are question marks.”