Sen. Elizabeth Warren, D-Mass., is raising concerns about whether recent rule changes at stock indexes cleared the way for SpaceX — and potentially OpenAI and Anthropic — to be included in indexes without some of the typical safeguards for investors.

The letter to the heads of the Nasdaq, S&P Dow Jones Indices, FTSE Russell and Morningstar Indexes sent on Thursday asked the companies whether they had made or considered rule changes based on lobbying from Elon Musk, other SpaceX officials or officials from OpenAI or Anthropic, and asked for any communications between the companies and the indexes. CNBC is first to report the letter.

Warren also detailed changes, or proposed changes the indexes had considered, including fast-tracking newly listed stocks into top indexes.

“The changes to your index rules to accommodate these large companies, however, have the potential to destabilize markets and create significant risks for American investors, especially retirees and other individuals that rely on index funds for their savings.”

SpaceX is set to begin trading on Friday and is poised to be one of the largest public offerings in history, with the company valued around $1.8 trillion. OpenAI and Anthropic also confidentially filed for IPOs as well.

Spokespersons for the four companies didn’t immediately respond to requests for comment.

Earlier this week, Warren called on the SEC to delay the SpaceX offering over concerns the agency had not done due diligence in protecting investors and market integrity.

Apollo’s John Zito had a blunt assessment of how private equity firms are valuing their software holdings as shares of comparable public tech companies have plunged: They’re not, he said.

Zito, co-president of the firm’s giant asset management division and its head of credit, spoke to clients of investment bank UBS last month in remarks first published by the Wall Street Journal. CNBC confirmed Zito’s comments.

“I literally think all the marks are wrong,” Zito told the clients. “I think private equity marks are wrong.”

For weeks, investors have punished the shares of public software companies on fears that the latest tools from Anthropic and OpenAI will make these companies obsolete. That has fed concerns that private credit lenders are sitting on stale valuations of their software loans, igniting a wave of redemptions as investors ask to withdraw funds from private credit vehicles.

Retail investors have pulled about $10 billion from private credit funds in the first quarter, according to analysis by the Financial Times. Amid the stampede, an array of industry leaders have sought to calm markets by explaining that the underlying companies are still performing well.

But sophisticated players including JPMorgan Chase are starting to act, reining in lending to private credit players by marking down the value of software loans.

While Wall Street figures including Jeffrey Gundlach and Mohamed El-Erian have flagged risks in private credit, Zito is among the first from within the industry to candidly acknowledge weakness in the market.

An Apollo spokesman declined to comment on Zito’s remarks. They come amid a tough backdrop for alternative asset managers, who’ve seen their shares battered this year. Zito and other Apollo executives have sought to draw a distinction between Apollo and other players in private credit.

Most of Apollo’s loans are to larger, more stable companies rated investment grade, and software makes up less than 2% of the firm’s total assets under management, Apollo told analysts last month. The firm has zero exposure to private equity stakes in software firms, it said.

Defense Secretary Pete Hegseth’s decision to label Anthropic a “Supply-Chain Risk to National Security” on Friday resulted in more questions than answers.

“It’s all very puzzling,” Herbert Lin, a senior research scholar at Stanford University’s Center for International Security and Cooperation, told CNBC in an interview.

Anthropic is the only American company ever to be publicly named a supply chain risk, as the designation has traditionally been used against foreign adversaries. But the company hasn’t received any official declaration beyond social media posts.

A formal designation will require defense vendors and contractors to certify that they don’t use Anthropic’s models in their work with the Pentagon.

The dispute centered around how Anthropic’s artificial intelligence models could be used by the military. The Department of Defense wanted Anthropic to grant the agency unfettered access to its Claude models across all lawful purposes, while Anthropic wanted assurance that its technology would not be tapped for fully autonomous weapons or domestic mass surveillance.

With no agreement reached by Friday’s deadline, President Donald Trump directed federal agencies to “immediately cease” all use of Anthropic’s technology, and said there would be a six-month phaseout period for agencies like the DOD.

Experts told CNBC the supply chain risk designation is highly unusual, especially since the U.S. and Israel began carrying out strikes in Iran just hours later. A group of retired defense officials, policy leaders and executives wrote to Congress on Thursday, defending Anthropic and calling the Trump administration’s designation a “dangerous precedent.”

Anthropic’s models are still being used to support U.S. military operations in Iran, even after the company was blacklisted, as CNBC previously reported.

Talks between Anthropic and the DOD are now reportedly back on, according to the Financial Times, but there are still big questions hanging over the issue as of Thursday.

Why is the U.S. government still using Claude?

Stanford’s Lin doesn’t understand why the DOD is still using Anthropic’s models in sensitive settings if they pose such a threat. If the Trump administration really sees Anthropic as a risk to national security, he said, it wouldn’t make sense to phase out the models over an extended period of time.

“OK, wait a minute, they’re a really dangerous player for U.S. national security, so you’re going to use them for another six months? Huh?” Lin said. 

Michael Horowitz, a senior fellow for technology and innovation at the Council on Foreign Relations, said it’s “especially notable” that Anthropic’s models were used to support the U.S. military action in Iran. He said “there’s no clearer signal” of how much the Pentagon values the technology.

“Even in a situation where there is this intense feud between the company and the Pentagon, they are using their technology in the most important military operation that the United States is conducting,” he said. 

Transitioning away from Anthropic toward a new vendor takes time and comes at a significant cost in terms of efficiency, said Jacquelyn Schneider, a Hargrove Hoover fellow at Stanford University’s Hoover Institution.

Until recently, Anthropic was the only AI company approved to deploy its models across the agency’s classified networks. OpenAI and Elon Musk’s xAI received clearance, but their systems can’t be deployed or adopted overnight.

What’s the actual threat?

By designating Anthropic a supply chain risk, the DOD is suggesting that the company is “really bad” for U.S. national security, Lin said. But he stressed that the agency hasn’t clearly outlined what kind of threat the company poses. 

“They don’t point to any technical failing, they don’t point to any hack,” Lin said. “They say things like ‘They’re arrogant,’ and ‘We don’t want you telling the DoD what to do in some hypothetical situation that hasn’t happened yet.'”

Lin said the other punishment that Hegseth was threatening to impose on Anthropic, invoking the Defense Production Act, also contradicts the idea that the company threatens national security. 

The Defense Production Act allows the president to control domestic industries under emergency authority when it’s in the interest of national security. It could essentially compel Anthropic to let the Pentagon use its technology. 

Horowitz said he thinks the clash between Anthropic and the DOD is “masquerading” as a policy dispute. 

Months earlier, venture capitalist and White House AI and crypto czar David Sacks criticized the company for “running a sophisticated regulatory capture strategy based on fear-mongering,” after an essay published by an executive, and conservatives have repeatedly accused Anthropic of pushing “woke AI.”

Anthropic CEO Dario Amodei took a different approach than other tech executives, avoiding getting cozy with the Trump administration in its early days.

“This feels to me like a dispute that is about politics and personalities,” Horowitz said. 

Is an official designation on the way?

Anthropic hasn’t been designated a supply chain risk by any official measure, and there’s an open question as to if or when the company should expect one. Defense contractors have to decide whether they will follow Hegseth’s directive on social media or wait for more formal guidance. 

Several executives told CNBC that their companies are moving away from Anthropic’s models, and a venture capitalist said a number of portfolio companies are switching “out of an abundance of caution.” But others, including C3 AI Chairman Tom Siebel, said he doesn’t see a “need to mitigate” the technology “until it gets litigated.” 

Schneider said businesses are rational, and if they think it’s high risk to work with Anthropic, whether it’s formally declared a supply chain risk or not, they’re going to hedge and look for other partners.

“There’s all sorts of decisions that have been made within the Trump administration that, by law, require more codification,” Schneider said. “Even the example of moving from DoD to [Department of War]. That by law needs more codification, but all the contractors are using DoW.”

Even so, Samir Jain, vice president of policy at the Center for Democracy and Technology, said social media posts likely aren’t enough to actually cause a designation.

“There’s a process that the statute requires, including an actual finding that Anthropic presents national security risks if it’s part of the supply chain,” he said in an interview. “I don’t think, factually, that that predicate could possibly be met here.”

Anthropic said in a statement Friday that it will challenge “any supply chain risk designation in court.”

Does this have anything to do with the U.S. strikes on Iran?

For Schneider, the war in Iran now looms large over the spat between Anthropic and the DOD. She said she’s left wondering whether the two conflicts were happening in parallel, or if they were somehow related. 

“Obviously, you’re not going to walk away from technologies that are deeply embedded in your wartime processes right before you go to war,” Schneider said.

She said planning a military operation of that magnitude would have required “a lot of sleepless nights,” so she was surprised the DOD was willing to spend such a “remarkable amount of energy” on a public clash ahead of the initial attack.

What happens next?

As the war in Iran stretches into its sixth day, Anthropic’s path forward with the DOD remains a big mystery.  

Horowitz said he would bet that the six-month off-boarding period will become a “a locus for some re-examination” within the Pentagon, especially since members of Congress and broader public markets have shown so much interest in the dispute. 

Lin expressed a similar sentiment, and said he wouldn’t bet on Anthropic’s models being out of the DOD a year from now.

Schneider is less convinced. 

“I wish I had a more definitive thought about where this is all going to go, but everything is so unprecedented,” she said. When it comes to historical examples or analogous cases, Schneider said: “I don’t have those. It’s just super limited.”

The DOD declined to comment. Anthropic didn’t provide a comment.

WATCH: Anthropic tops $19 billion in annual revenue rate

BEIJING — Uncertainty is growing over U.S. President Donald Trump’s high-stakes trip to China after Washington targeted a second foreign leader in two months.

Trump announced over the weekend that joint U.S.-Israel strikes on Iran killed its Supreme Leader Ayatollah Ali Khamenei. In early January, the U.S. also captured Venezuelan leader Nicolas Maduro and his wife from their residence.

Analysts say those actions could complicate Trump’s high-stakes trip to Beijing.

“President Xi Jinping won’t feel easy about the death of the top leader of Iran,” said George Chen, partner at The Asia Group, noting Beijing’s relatively good relations with Tehran and Caracas.

“How can Xi feel everything is normal and alright and be prepared to welcome Trump to visit in [a] happy mood?” he said. Chen added that “investors should manage their expectations on what Trump can achieve for his China trip — if he still goes.”

Trump is scheduled to visit Beijing from March 31 to April 2, following a fragile trade truce with China reached in late October. It would mark the first trip by a sitting U.S. president since 2017.

But Beijing has yet to confirm the dates.

China’s Foreign Ministry on Sunday condemned Khamenei’s killing and called it “a grave violation of Iran’s sovereignty and security.” Beijing urged for an immediate ceasefire, although it was less direct about the U.S. role than it had been after Maduro’s capture.

“I worry the U.S. side might use Iran, if it’s going poorly, to delay the trip,” said a foreign business executive tracking meeting preparations very closely, who requested anonymity due to the sensitivity of the matter.

“I think the risk [of the trip falling apart] is on the U.S. side more than the Chinese side,” the executive added.

U.S.-based prediction markets signaled a greater likelihood of a delayed Trump trip.

As of late Monday morning, Polymarket showed a sharp drop in expectations that Trump would visit China by March 31, to 42%, from 83.9% on Feb. 21, while wagers on a visit by April 30 remained high at 81%.

Kalshi showed a slight drop in expectations that Trump would visit China by 2027, though it remained a high 91%.

While many analysts still expect the trip to proceed, it’s less clear how U.S. businesses will navigate plans for deals in the world’s second-largest economy.

Several U.S. executives had been expected to accompany Trump on his Beijing trip, following a pattern of business delegations following leaders of different countries on their trips this year to China in a bid to strike deals.

“Prior to the attack on Iran, many American CEOs were already unwilling to go with Trump to China. Now the situation is even more tricky,” according to an active member of the American business community in China, who also requested anonymity due to the sensitivity of the matter.

The White House and China’s Foreign Ministry did not immediately respond to a CNBC request for comment.

The Chinese readout so far indicates an “unusually softer tone,” said Jack Lee, analyst at China Macro Group. He expects Trump to visit Beijing as planned, but is watching whether Washington signals restraint on arms sales to Taiwan.

The democratically self-ruled island, claimed by Beijing, remains a central flashpoint in U.S-China relations.

Trump, meanwhile, told British newspaper the Daily Mail that U.S. strikes on Iran could last four weeks — a point that Chinese state media highlighted Monday morning. That timeframe would run into the planned March 31 start date for his trip to China.

“If the conflict escalates into a regional war beyond what the U.S. originally planned, it’s not impossible that Trump might delay the trip,” said Yue Su, principal economist at the Economist Intelligence Unit.

“Still, I expect Trump and [Xi] to have a phone conversation about this at some point,” she said. Her base case remains that Trump goes ahead with his China trip later this month.

China this week kicks off an annual parliamentary meeting, where top diplomat Wang Yi typically speaks to the press. In mid-February, Wang told U.S. Secretary of State Marco Rubio on the sidelines of the Munich Security Conference that the U.S. and China should work to expand areas of cooperation.

In foreign policy, Beijing has prioritized its own interests by forging bilateral ties while encouraging multilateral engagement. Official statements around past U.S.-China meetings have noted the need to create “conditions” for developing bilateral relations.

The U.S. actions in Iran have eroded trust between the two countries, said Dong Shaopeng, a senior researcher at Renmin University of China. While he still expects Trump and Xi to meet in a few weeks, he said he hopes the conflict does not spread to other countries in the Middle East.

State-affiliated Chinese columnist “Niutanqing” on Monday described the Iran “war” as more intense than the conflict in Ukraine, drawing several lessons. Of the several lessons from the turn of events, the columnist said that Khamenei’s death revealed “traitors” can emerge from within, and that negotiations may conceal the true intentions of an adversary, according to a CNBC translation of the post in Chinese.

If the Trump-Xi meeting proceeds as planned, it could offer an opportunity for broader peace talks while addressing strained U.S.-China relations.

“The issues that they have to work out, China-U.S. trade, are pretty important, and the meeting has been scheduled to be in place for a long time, and so cancelling it would be pretty radical at this point,” said Gary Dvorchak, managing director at Blueshirt Group.

“I don’t think it would … help the situation to cancel the meeting for any reason.”

BondBloxx ETFs has been making a big bet in private credit.

Even with Wall Street fears of an impending meltdown in the space, the firm’s co-founder and chief operating officer is confident private credit is a sensible way for investors to pursue income.

“What you’re seeing in the press… maybe a fund of one manager and one manager’s assets [are] being marked down, and that’s going to happen. There may be a concentration in that manager’s approach or in the loans and the companies that are in their fund,” Joanna Gallegos told CNBC’s “ETF Edge” this week.

Gallegos, who’s the former head of global ETF strategy at J.P. Morgan Asset Management, contends BondBloxx’s approach to private credit protects investors because it’s designed to give “immense diversification.”

“Because of the way it’s [BondBloxx Private Credit CLO ETF (PCMM)] structured, you’re getting exposure to almost over 7,000 of those loans,” she said. “It gives you a pure play to private credit because 80% of the exposure in that product is private credit. And I think there’s been a lot of discussion about other vehicles and ETFs that there may not be 100% private credit.”

The firm launched its BondBloxx Private Credit CLO ETF in December 2024 — promoting it as the first-ever ETF that offers investors direct exposure to private credit.

As of Wednesday’s market close, FactSet reports the fund is up 7% since its inception and up 2% over the past three months.