If it weren't for the intense rivalry between Anthropic and OpenAI, the boom in generative artificial intelligence might not have arrived so quickly. In late 2022, OpenAI learned that Anthropic was developing an AI-based chatbot. Faced with the information, OpenAI CEO Sam Altman ordered employees to accelerate the launch of a competing product, according to four people familiar with the matter. Two weeks later, the company launched ChatGPT, ushering in a technological revolution that promises to transform the global economy and the way people interact. The same urgency now extends to the two companies' IPO plans. Anthropic and OpenAI compete for who will reach the stock exchange first. Both see an early debut as a way to influence the way investors evaluate the sector and consolidate their CEOs as the main voices in artificial intelligence. Until May, many advisors believed that OpenAI would come out ahead. According to sources interviewed by Reuters, the company informed some investors that it intended to launch its initial public offering (IPO) in September. But Anthropic got ahead of itself. On June 1, it announced that it had confidentially filed the necessary documents with American regulators. OpenAI did the same a week later. The dispute goes beyond the clash between Altman and Anthropic's CEO, Dario Amodei, a former OpenAI researcher and one of those responsible for the technology that made ChatGPT possible. Competition has also reached Wall Street. It is rare that two direct rivals of such size seek to raise funds at the same time. Because the offerings will be gigantic, companies are turning to some of the same investment banks. OpenAI intends to go public with a valuation close to US$1 trillion, according to information previously released by Reuters. Bankers and consultants involved in the processes need to deal with increasingly delicate relationships with both companies. According to sources, executives from both pressure their advisors in search of information about the competitor's plans. To prevent leaks, some banks created internal barriers between the teams working on each operation. "Total War" Conflicts between top executives are nothing new. Elon Musk and Jeff Bezos have exchanged public criticism for years over the space race. Bill Gates and Steve Jobs were also involved in disputes over alleged copies between Microsoft and Apple products. But the tension between Altman and Amodei became one of the drivers of today's biggest technological revolution. It influences the speed at which new AI tools are released, the resources they receive and, ultimately, the way the technology is used in everyday life. "It's a total war between them," said Anastasios Angelopoulos, CEO of Arena, a company specializing in evaluating AI models. "Every time Anthropic launches something new, the bet is that OpenAI will respond quickly — and vice versa." The two companies declined to comment on the rivalry between executives. Dispute over revenue The divergences also involve the way each company presents its financial numbers to investors. According to sources interviewed by Reuters, OpenAI has told investors and employees that the accounting methodology used by Anthropic overestimates the company's revenue by billions of dollars. In April, OpenAI Chief Revenue Officer Denise Dresser told employees that the company considers its rival's financial results to be inflated, according to an internal memo obtained by Reuters. The difference is in the way revenue is recorded. Anthropic records as revenue the total amount paid by customers for its AI services. Part of this money, however, is later passed on to partners such as Amazon and Google. OpenAI uses another method and only records net revenue, discounting payments made to Microsoft. Anthropic told Reuters that it follows consolidated accounting practices and records gross revenue because it is primarily responsible for the transaction, while cloud computing partners act only as distribution channels. Dresser's internal communications were intended to reassure OpenAI employees concerned about their rival's rapid growth. For Gil Luria, an analyst at D.A. Davidson, the race to go public first is also related to this dispute. "One reason Anthropic wants to get to market early is to set the standard for how cutting-edge AI companies present their financial results in a way that is favorable to their own business model," he said. Internal pressure The desire to surpass the competitor also caused tensions within OpenAI. Altman recently clashed with Chief Financial Officer Sarah Friar over the company's ability to meet all the requirements needed for an IPO on such a tight deadline, according to three sources. According to these people, Altman told her she should find a solution or hire other bankers and lawyers who were capable of carrying out the plan. Later, Friar informed advisors that the company's leadership is aligned regarding the schedule. In an interview with CNBC after Anthropic's announcement, Altman stated that he does not intend to rush OpenAI's public debut. An old rivalry The dispute began at the end of 2020, when Amodei left his position as vice president of research at OpenAI and founded Anthropic with other former employees. The new company promised to prioritize the security of AI systems. Within OpenAI, many saw the decision as a criticism of the way Altman ran the company. In early 2022, Anthropic trained the first version of the Claude chatbot, but chose not to launch it immediately to conduct additional security research. OpenAI also developed similar projects. Part of the team worked on a tool internally called "super assistant", while co-founder John Schulman developed a conversational interface. At one point, the company even considered launching the assistant in March 2023, along with GPT-4. But rumors about the Anthropic project changed plans. According to one of the sources, Altman ordered OpenAI to bring a chatbot to market as quickly as possible. “Suddenly everything turned around: We need to launch this in two weeks.” The result was ChatGPT, launched on November 30, 2022. The product became the fastest-growing consumer app in history, attracting millions of users and altering the development plans of the biggest technology companies. Anthropic launched Claude a few months later and spent about three years trying to catch up to its rival. In late 2024, Amodei redirected researchers to focus on so-called reasoning models after observing OpenAI's early success in this area. The dynamic changed again at the end of 2025, when Anthropic released a powerful update to Claude Code, a programming tool. OpenAI, which still derives a large part of its revenue from ChatGPT subscriptions, has once again intensified investments in corporate software and increased resources allocated to Codex, its product for code development. Relationship getting worse Relations between the companies deteriorated after Altman's unexpected dismissal by OpenAI's board at the end of 2023. At the time, board members briefly discussed the possibility of uniting the two laboratories under Amodei's leadership. In a recent statement, a former OpenAI executive said the idea was considered for an "extremely short" period before being scrapped. Still, the news infuriated many OpenAI employees. Altman returned to office a few days later, but resentment remained. The rivalry also began to occur in public. In February, Altman criticized Anthropic ads shown during the Super Bowl, calling them "misleading" for suggesting that OpenAI intended to sell advertising within ChatGPT. The following month, Amodei accused Altman of using Anthropic's dispute with the Pentagon to benefit OpenAI. During a summit on artificial intelligence held in India in February, Prime Minister Narendra Modi encouraged executives present to join hands as a show of unity. In a scene that went viral on social media, Altman and Amodei, who were side by side on stage, refused the gesture.