Takeaways from the congressional report on Big Tech.

The New York Times: Amazon sets the rules for digital commerce, and Apple favors its own apps and services on its devices. Facebook holds “firmly entrenched” monopoly power over social networking. Google has maintained its search dominance by grabbing information from third parties without permission to improve search results.

Those are some of the findings from a sweeping report by House lawmakers accusing four of the world’s largest tech companies of abusing their market power. The document, which was released on Tuesday, concludes a 15-month investigation.

Read more of our coverage of the report:

House Lawmakers Condemn Big Tech’s ‘Monopoly Power’

In a 449-page report that was presented by the House Judiciary Committee’s Democratic leadership, lawmakers said the four companies had turned from “scrappy” start-ups into “the kinds of monopolies we last saw in the era of oil barons and railroad tycoons.” The lawmakers said the companies had abused their dominant positions, setting and often dictating prices and rules for commerce, search, advertising, social networking and publishing.

To amend the inequities, the lawmakers recommended restoring competition by effectively breaking up the companies, emboldening the agencies that police market concentration and throwing up hurdles for the companies to acquire start-ups. They also proposed reforming antitrust laws, in the biggest potential shift since the Hart-Scott-Rodino Act of 1976 created stronger reviews of big mergers.

12 Accusations in the Damning Report on Amazon, Apple, Facebook and Google

Amazon harvests the sales and product data from its marketplace to spot hot-selling items, copy them and offer its own competing products, typically at lower prices.

Apple has used its control over the App Store to punish rivals, including by ranking them lower in search results, restricting how they communicate with customers, and removing them outright from the store.

Facebook has grown so overwhelmingly powerful that internal findings suggest its greatest competition exists within itself.

Google maintained its search monopoly by grabbing information from third parties without permission to improve search results.