Chief information officers from 87 large US corporations sent an open letter to the House Ways and Means Committee on Saturday urging members to exempt enterprise users from the Senate-passed moratorium on frontier-scale AI training, opening a new front in a lobbying battle that until now has been dominated by hyperscaler chief executives and the bill’s progressive sponsors.

The letter, organized by a working group convened under the auspices of the Business Roundtable’s technology council, was signed by technology chiefs at banks, insurers, hospital systems, retailers, manufacturers and one of the country’s two largest railroads, according to a copy reviewed Saturday and confirmed by three signatories. It is the first organized intervention by buyers of large-scale AI services in a debate that has so far been framed almost entirely as a fight between sellers — Microsoft, Alphabet, Amazon Web Services and Meta — and progressive lawmakers led by Sen. Bernie Sanders, I-Vt., and Rep. Alexandria Ocasio-Cortez, D-N.Y.

“Our companies are not building frontier models. We are buying capacity to detect fraud, schedule operating rooms, route freight and answer customer calls,” the letter states. “A pause defined by compute thresholds will reach far beyond the four or five firms it was written to constrain.”

The signatories include the CIOs of three of the four largest US commercial banks, the chief technology officers of two major health insurers, and technology leaders at a cluster of industrial manufacturers in Ohio, Indiana and South Carolina. The letter was coordinated by Helena Marchetti, executive director of the Roundtable’s technology policy program, and drafted over a 72-hour period beginning Wednesday evening, after the hyperscaler CEO sweep through Capitol Hill drew renewed attention to the bill’s text.

“This is not a hyperscaler letter wearing a different jacket,” Marchetti said in a Saturday interview. “Our members have spent the last week reading the actual statute and asking their general counsels what a training-run pause means for the workloads they have already built. The answer they are getting is that nobody is sure, and that uncertainty is its own form of damage.”

The Senate-passed measure, approved 52-48 on Apr. 7, imposes an 18-month moratorium on training runs above a defined compute threshold and requires federal licensing for new datacenter projects exceeding 500 megawatts of contracted load. Its sponsors argue that the buildout’s strain on regional power grids, surging residential electricity rates in datacenter corridors, and accelerating model capability all justify a structured pause.

Sanders, in a statement issued Saturday evening, said the CIO letter “confirms what we have been hearing privately from procurement officers across the economy: enterprise buyers want clarity, and they want grid stability, and they want a Congress that does not roll over for four trillion-dollar firms.”

He pledged to incorporate “narrow technical clarifications” into a manager’s amendment if the committee proceeded to markup Monday, but said the underlying training-run cap was “not negotiable.”

The legislative arithmetic in Ways and Means has tightened in recent days. The committee splits 24-21 in the majority’s favor, but four Democrats have signaled concern about the moratorium’s reach, and two Republicans have voiced cautious support for its grid-protection provisions. The CIO letter is widely expected to give wavering members on both sides additional political cover.

“The pressure on members had been very one-sided,” said Dr. Eduardo Reyes, a political scientist at George Washington University who tracks technology legislation. “You had the hyperscalers, who members are skeptical of, on one side and the sponsors on the other. The arrival of a Fortune 500 buyer coalition changes the geometry. These are companies with employees in every district.”

The letter draws specific attention to three categories of workloads its signatories say should not be captured by the bill. The first is continued training on proprietary corporate data — for example, an insurer refining its claims-routing model on internal records. The second is fine-tuning of existing foundation models to specific industries. The third is the operation of agentic systems that already use frontier-scale models under existing contracts.

“You can argue about whether the next GPT-class run should be paused,” said Rajiv Bhattacharya, chief information officer at a midwestern hospital system that signed the letter. “What you cannot do is write a statute that accidentally makes it illegal for us to keep training our sepsis-prediction model on our own patient charts. Read literally, that is what the current bill does. I am hopeful members will see that we are not the target.”

Industry analysts cautioned that the letter would not, on its own, sink the moratorium. “Buyers are influential but they are not the loudest voice in the room,” said Nora Whitlock, a senior analyst at Bernstein covering enterprise software. “The signal here is not that the bill dies. The signal is that the committee will not pass the Senate text untouched. There will be carve-outs, and the carve-outs will be where the next month of fighting happens.”

A senior House Democratic aide, speaking on condition of anonymity to describe internal whip operations, said three of the four wavering Democrats had asked the sponsors’ staff Saturday afternoon for a written response to the CIO letter, and that a draft was expected to circulate Sunday.

Ocasio-Cortez, asked at an unrelated event in the Bronx Saturday afternoon whether the enterprise letter changed her view, was blunt. “Bank CIOs were not in the room when the grid in Phoenix gave way last summer,” she said. “I take their concerns seriously and we will read every line. But the bill is about a planetary build-out, not about a hospital’s scheduling model, and we are going to make that distinction clear in markup.”

Markup is scheduled to begin at 10 a.m. Monday in Longworth 1100. Committee staff said the chairman had not yet decided whether to consider the bill as a single combined vote or to break it into severable provisions, a procedural choice that several members described as potentially decisive. Aides on both sides said they expected amendments to be filed through Sunday evening.