The new Fortune 500 list—the iconic benchmark of success for American corporations—is out this morning. Once again, Walmart took top honors, and Exxon Mobil scored second. But there were some big movers in the tech world: Apple displaced Berkshire Hathaway for the #3 spot, and Amazon cracked the top five for the first time, moving up from No. 8 last year.

As Fortune’s Erika Fry points out, the list is getting increasingly top heavy. The top 50 firms earned 47.7% of all Fortune 500 revenues. That’s up from 46.9% last year, 43.7% 15 years ago, and 41% in 1995. Given recent mergers—CVS-Aetna, AT&T-Time Warner, Marathon-Andeavor—it’s possible the top 50 will account for half of all revenues by the time of next year’s list.

Some of that reflects the inevitable tendencies in today’s tech-driven world, where zero-marginal-cost businesses and scale economies create winner-take-most outcomes. And some reflects the fact that regulators haven’t figured out how to deal with legacy companies that insist they have to merge to compete with their data-rich tech competitors. But it should be no surprise to anyone, given this trend, that antitrust laws are starting to get a second look.

Also this morning, we are putting out more results from our Fortune 500 CEO poll. A few takeaways:

–61% of Fortune 500 CEOs think the economy will stay the same over the next 12 months; only 21% think it will get worse. And slightly over half think a recession won’t hit in the next two years.

–76% think the Federal Reserve has been “just right” in its conduct of monetary policy.

–And 74% say the U.S. remains the best region for them to invest over the next two years.

You can explore the list here, read Erika Fry’s essay on scale here, and see the poll data here.

More news below.

Top News

Huawei Ban

President Trump has signed the predicted executive order that effectively bans Huawei from U.S. telecoms networks. But there's more: the Commerce Department has added Huawei to its "entity list," which threatens the Chinese firm's ability to use U.S. technology in its products. Huawei says its equipment poses no national security threat to the U.S. or anywhere else, and it is "willing to sign no-spy agreements with governments" to prove it. Al Jazeera

Trump Pardon

Trump has pardoned the fraudster and former media mogul Conrad Black, who last year published a favorable biography of Trump. The White House said Black, who served a few years in U.S. jail a decade back, had made "tremendous contributions to business, as well as to political and historical thought." Black defrauded shareholders in his company, Hollinger International, of more than $6 million. BBC

PG&E Fire

Californian investigators have pinned the state's deadliest wildfire on a faulty PG&E transmission line near the town of Pulga. The finding adds extra pressure to the utility, which is already facing enormous liability costs. Wall Street Journal

Brexzzzit

It's back! British Prime Minister Theresa May will ask Parliament to vote for a fourth time on the Brexit deal it has already rejected three times. The vote will take place in early June. Will she succeed this time? Deeply unlikely—she and opposition leader Jeremy Corbyn have failed to strike any kind of deal between themselves, and Parliament remains as divided as ever. It’s been said before so it should be said with caution, but May is probably not going to remain prime minister for much longer. Politico

Around the Water Cooler

Female CEOs

This year's Fortune 500 list includes 33 companies with female CEOs—just 6.6% of the total, but a huge leap forward from last year's total of 24. Two of the companies have had female CEOs for a long while but have now entered the Fortune 500. Several other companies, such as Best Buy and Northrop Grumman, were already on the list but have now appointed female chief executives. Fortune

Huawei Persecution

Bloomberg opinion columnist Tim Culpan reckons the White House and Commerce Department have given Huawei a golden opportunity to claim persecution by the Americans. The U.S. still hasn't provided evidence of Huawei's supposedly espionage-enabling equipment flaws. Culpan: "The U.S. actions feed a narrative that the campaign against Huawei is political rather than security-related. That could be a useful campaign tool as the company looks to ply its wares in more amenable nations." Bloomberg

China Arrests

China has now formally arrested two Canadians that it detained last year. Michael Spavor and Michael Kovrig are apparently suspected of gathering state secrets for foreign forces. Spavor and Kovrig were detained shortly after Canada arrested Huawei CFO Meng Wanzhou, who faces deportation to the U.S. Spavor is a businessman; Kovrig works for the International Crisis Group conflict-resolution NGO. Reuters

Occidental and Anadarko

Fortune's Jen Wieczner provides a deep dive into the Occidental-Anadarko merger, which was partly financed by Berkshire Hathaway. "For years, the sector burned so many investors that many abandoned it," she writes. "But the Occidental deal may have reignited interest. It’s funny what $10 billion from Warren Buffett will do." Fortune

This edition of CEO Daily was edited by David Meyer. Find previous editions here, and sign up for other Fortune newsletters here.