The U.S. Federal Trade Commission should launch an investigation into the growing consolidation of big data analytics firms and digital marketing companies, a coalition of four privacy groups said Friday.

A recent spate of acquisitions in the big data and digital marketing industries raises privacy concerns about “companies amassing vast holdings of the key element that drives much of online commerce”—information about consumers, said the groups in a letter to FTC Chairwoman Edith Ramirez.

The four privacy groups—the Center for Digital Democracy [CDD], U.S. PIRG, Consumer Watchdog, and Public Citizen—raised particular concerns about Oracle’s agreement, announced in December, to acquire data broker Datalogix. The transaction gave Oracle, in its words, access to the “the world’s most valuable data cloud” for digital marketing and for connecting consumers’ various identities across “all devices, screens and channels.”

The FTC approved Oracle’s acquisition of Datalogix about three weeks after the companies announced it. There were more than 200 mergers and acquisitions in the marketing and advertising technology industries in the first half of 2014, according to Results International, a U.K. business consultancy.

The company’s purchase of Datalogix should have triggered a more extensive review by the FTC, given the agency’s expertise of the digital data industry, the privacy groups said. Oracle also acquired data broker BlueKai last year.

The Oracle and Datalogix deal “reflects the digital data arms race underway where companies are amassing powerful and detailed sets of information to track and target a consumer anywhere, anytime,” Jeff Chester, CDD’s executive director, said by email.

The combined data sets of Oracle and DataLogix include information about consumers’ finances, race, locations and other sensitive data, the groups said. The merger touches on several consumer-protection matters, including financial marketing and auto sales, where the FTC has a congressional mandate to protect the public, the groups said.

Representatives of Oracle and the FTC declined to comment on the letter from the privacy groups.

U.S. regulators need to take a hard look at new big data mergers, said Rob Weissman, president of Public Citizen.

With big data mergers continuing, “a handful of data titans hope to aggregate personal and private data about everyone, so they know where we go, what we do, whom we see, what we want, what we think and what we say,” Weissman said in a statement. “There’s no reason for us to be racing toward a dystopian future of total surveillance.”