WASHINGTON — House lawmakers on Friday pressed experts on how the market power of major tech platforms could hurt consumer privacy, showing that an antitrust investigation into Facebook, Google, Apple and Amazon is growing to include deeper questions about their business models.

Lawmakers from the Judiciary Committee heard testimony that the tech giants have amassed vast quantities of data that give them an advantage over rivals, and that their dominance allows them to get away with more aggressive data collection.

But some Republicans expressed concerns that efforts to regulate privacy, including aggressive data protection regulations in Europe, could hurt competition among internet firms.

The hearing was the latest in a wide-ranging antitrust investigation by the House into the companies. Google has also disclosed that it is the subject of a Justice Department investigation, while Facebook said this year that the Federal Trade Commission was looking at its practices. State attorneys general are investigating the two companies as well.