Meruelo expanded his business focus, founding the Meruelo Group, which has grown into a construction and real estate development firm. Meruelo Group has ownership of Neal Electric Corp, Select Electric Inc., and Doty Bros within the Southern California area. The group also owns Commercial Bank of California. which Meruelo co-founded in 2003, Spanish-language independent television station KWHY-TV, radio stations KLOS, KLLI, KPWR, KDAY and KDEY-FM under the Meruelo Media banner, and the Grand Sierra Resort in Reno, Nevada.

In May 2008, Meruelo purchased a 8,500-square-foot, $7.05 million house at 36 Indian Creek Drive in Miami. In March 2014, he acquired a $10.79 million penthouse in The Langham, New York. In June 2018, he purchased Colom Island in Spain for 3.2 million euros.

Meruelo purchased food manufacturer and the largest provider and distributor of pre-packaged sushi in the United States Fuji Food in 2009.

In September 2011, Meruelo announced a $25 million investment in the renovation of the Grand Sierra Resort in Reno, Nevada.

In November 2011, Meruelo’s bid to take ownership of the Atlanta Hawks of the National Basketball Association from the team’s then owners Atlanta Spirit was turned down. The team was later sold to Tony Ressler in 2015. In June 2019, he purchased majority ownership of the Arizona Coyotes of the National Hockey League from previous sole owner Andrew Barroway who retained a minority stake. With his purchase of the Coyotes, Meruelo became the first Latino owner in the NHL.

In February 2013, the Meruelo Group made a bid to buy Donald Trump’s Trump Plaza Hotel and Casino for $20 million. The deal fell through and the casino closed the following year.

The SLS Las Vegas (formerly the Sahara Hotel and Casino) in Las Vegas, Nevada, was purchased by the Meruelo Group on June 2017. Alex Meruelo plans to turn the casino into a favorite destination for the Hispanic community. Meruelo plans to use its media properties to advertise the casino and its events. In May 2019, SLS brand owner SBE Hotel Licensing, LLC filed a lawsuit alleging that Meruelo’s Las Vegas Resort Holdings, LLC had failed to pay at least $450,000 in licensing fees since November 2018. On June 28, 2019 The Meruelo Group and Alex Meruelo announced plans to rename the SLS Hotel as The Sahara Las Vegas. On August 29, 2019 the Meruelo Group officially changed the SLS Hotel to Sahara Las Vegas and is located on Sahara Blvd.