The U.S. Supreme Court struck down the federal ban on sports betting in a 2018 decision, opening the doors for states to legalize it if they wish. Since then, more than 30 states and the District of Columbia have legalized sports betting in some form, many allowing online bets. Another 10 states could legalize the practice in the near future.

As more states legalize sports betting, the market is growing quickly. Not only are new states easing restrictions, but betting is growing more popular each year in states that have already legalized it. If you want to invest in this quickly growing industry, here are seven options to consider:

A person placing a sports bet on a smartphone.

Image source: Getty Images.

1. Flutter Entertainment

Flutter Entertainment (LSE:FLTR)(OTC:PDYP.Y) is a sports betting and gaming company operating in the UK, Ireland, Australia, and the United States. Among its U.S. properties is FanDuel, the most popular online sports betting site in the country. Flutter estimated FanDuel's share of online sports betting had grown to about 40% by the end of 2021.

FanDuel's online sportsbook is available in 14 states, and its online casino is available in five. The company got a big boost at the start of 2022 when online sports betting went live in New York, a massive market. Flutter was among nine companies that won an operating license from the state.

Outside of the U.S., Flutter is also the leading operator in the more mature UK and Ireland market. That market is the largest in Europe, and, as more betting shifts online, Flutter is well-positioned to win a greater share. In Australia, it operates SportsBet, which Flutter claims holds a 50% market share of online sports betting, a share that's continuing to grow.

2. DraftKings

DraftKings (NASDAQ:DKNG) operates the second-largest online sportsbook in the U.S., accounting for about 25% of the market, according to its internal estimates. It currently operates in 17 states, and its online casino is available in five. 

Draftkings is solely an online operator in the U.S. It doesn't have any brick-and-mortar casinos or international operations, so it's a pure play on the growth of online sports betting in the U.S. While that gives the company great growth potential considering the expected expansion of online sports betting in the U.S., it also means it's currently investing heavily in growth. 

Management says its launches in states such as New Jersey and Illinois suggest a payback period of less than three years for entering new markets. And it's seen stronger signups in new states as its national marketing efforts address pent-up demand. Consequently, DraftKings could see its growth rates remain robust as new states legalize online sports betting and gaming.

3. MGM Resorts

MGM Resorts (NYSE:MGM) is one of the biggest casino operators in the U.S. and Macau. It also jointly owns BetMGM with Britain's Entain. BetMGM says it's on track to take a 20% to 25% share of the U.S. online sports betting and gaming market, but that may heavily favor the gaming business. It had a 30% share in the markets where it operates its online casino at the end of 2021.

MGMs brick-and-mortar operations are starting to recover from the impact of the COVID-19 pandemic. Las Vegas traffic is starting to return, and the company ought to eventually exceed its pre-pandemic levels with a new NFL team drawing increased traffic to the city. MGM is opening two new hotels in 2022 and 2023 to support the growth. It should also see operations in Macau recover and may enter the Japanese market later in the decade.

Three sports fans cheering.

Image source: Getty Images.

4. Caesars Entertainment

Caesars (NASDAQ:CZR) is best known for its Caesars Palace casino in Las Vegas, but, after its acquisition by Eldorado (which took the Caesars name), it now operates more than 50 casinos across the U.S. The company then acquired William Hill, which pushed it into the online sportsbook market in the U.S. It rebranded William Hill's operations to Caesars Sportsbook.

The company has been aggressively marketing its online sportsbook with national campaigns, leading it to take double-digit market share. However, it's also producing significant losses for the company, prompting management to decide on a more tactical and targeted approach to its ad campaigns going forward as more states legalize sports betting.

Caesars will likely continue to focus on acquiring brick-and-mortar casinos to add to its growing portfolio. Meanwhile, it's building two more casinos in Las Vegas. Its operations in Macao and Singapore hold potential as well after facing big setbacks from the pandemic.

5. Penn National Gaming

Penn (NASDAQ:PENN) operates 44 casinos across 20 states, and it moved into the world of online sports betting with the acquisition of a 36% stake in BarStool in 2020 and theScore in 2021. Its online sportsbook has licenses in 13 states, and its online casino is available in five. Two dozen of its brick-and-mortar casinos operate retail sportsbooks.

Penn has been less aggressive in marketing its online sportsbook, sticking to more targeted ads versus nationwide brand campaigns. It's also been a beneficiary of BarStool's and theScore's media segments for more organic advertising of its sportsbook. As a result, the company has been more profitable than other online sportsbooks, which invest heavily in marketing.

With operations confined to the U.S. and Canada, Penn is more of a pure play on the continued expansion of sports betting in North America.

6. fuboTV

fuboTV (NYSE:FUBO) is a virtual multichannel video programming distributor with a heavy focus on sports. While traditional pay-TV companies are seeing subscribers cut the cord, fubo is growing. It counted more than 1 million subscribers by the end of 2021, and it expects to reach 1.5 million by the end of 2022.

The company plans to integrate an online sportsbook into its video streaming product, which is already operating in two states, and it has licenses for 10 more states. Instead of going after the same sports bettors as established rivals in the space, fubo plans to use its built-in subscriber base to prompt sports fans to become casual bettors. That could mean reduced marketing expenses and improved profitability for the sportsbook.

The sportsbook could also have benefits for the pay-TV business. Bettors are more likely to tune into games, which can help increase advertising for fubo. The company has several media rights for sporting events, for which it can collect 100% of the ad revenue, and the sportsbook could lead to greater viewership of those broadcasts.

fuboTV offers investors a unique entry point into the online sports betting market.

7. Roundhill Sports Betting & iGaming ETF

For investors looking for broad exposure to the sports betting and online gaming industry without picking individual stocks, the Roundhill Sports Betting & iGaming ETF (NYSEMKT:BETZ) invests across a portfolio of stocks in the industry. The fund currently holds more than 40 different positions, including several of the names mentioned above. Its expense ratio of 0.75% isn't too high for a specialized index fund.

Investors should be aware that this ETF has high exposure to online gaming as well as sports betting. Investments include sportsbooks, technology for enabling online sportsbooks, casinos, and online gaming. It's also heavily invested in international stocks, which make up more than two-thirds of its holdings. That could change, however, as the U.S. market for sports betting grows relative to the rest of the world.

For investors looking for a simple way to gain exposure to sports gambling, a small position in this ETF could be worth a bet.