By Thursday, Google will have changed how it displays certain search results. Microsoft will no longer force Windows customers to use its Bing internet search tool. And Apple will give iPhone and iPad users access to rival app stores and payment systems for the first time.

The tech giants have been preparing ahead of a Wednesday deadline to comply with a new European Union law intended to increase competition in the digital economy. The law, called the Digital Markets Act, requires the biggest tech companies to overhaul how some of their products work so smaller rivals can gain more access to their users.

Those changes are some of the most visible shifts that Microsoft, Apple, Google, Meta and others are making in response to a wave of new regulations and laws around the world. In the United States, some of the tech behemoths have said they will abandon practices that are the subject of federal antitrust investigations. Apple, for one, is making it easier for Android users to interact with its iMessage product, a topic that the Justice Department has been investigating.

“This is a turning point,” said Margrethe Vestager, the European Commission executive vice president in Brussels, who spent much of the past decade battling with tech giants. “Self-regulation is over.”

For decades, Apple, Amazon, Google, Microsoft and Meta barreled forward with few rules and limits. As their power, riches and reach grew, a groundswell of regulatory activity, lawmaking and legal cases sprang up against them in Europe, the United States, China, India, Canada, South Korea and Australia. Now that global tipping point for reining in the largest tech companies has finally tipped.

The companies have been forced to alter the everyday technology they offer, including devices and features of their social media services, which have been especially noticeable to users in Europe. The firms are also making consequential shifts that are less visible, to their business models, deal making and data-sharing practices, for example.