What did investors take away from the four Big Tech companies reporting earnings late yesterday?

• If you're going to spend big on AI, you better have the growth to justify it.

Why it matters: Investors are fed up with CEOs hyping AI and ready for CFOs to start explaining the return on their AI spending.

Driving the news: Google parent Alphabet, Microsoft, Amazon and Facebook parent Meta all announced plans yesterday to increase spending on their AI buildouts this year, enormous outlays of cash that could total as much as $700 billion.

Zoom in: The spending sprees came with different stories, however.

• Alphabet reported an 81% increase in profits, and its AI tool Gemini for enterprise's active user base grew 40% quarter over quarter. Its shares surged 4% in after-hours trading.
• Meta, meanwhile, raised its estimate range for capital expenditure to as much as $145 billion from $135 billion, yet its guidance for revenue was only in line with investors' expectations. Its shares fell more than 6%.
• Microsoft broke out its AI-specific revenue, saying it was up 123% year over year.

Between the lines: Investors want more of what Microsoft and Alphabet delivered: fundamentals that show how the investment in AI is paying off in revenue.

• Meta did not break out AI-specific revenue contributions.

Threat level: Spending on AI shows no signs of slowing any time soon.

• Memory is getting more expensive due to shortages, and even as chips get more efficient, companies have to buy the newest ones to keep up.

Yes, but: The four companies also put up double-digit growth across multiple lines of business.

• Some of that serves as moats that allow those businesses to continue to bet big on their AI ambitions.

The bottom line: Get ready to break out AI-related returns on the next quarterly call or be prepared to face the wrath of investors.

The U.S. is producing so much natural gas that at one hub in West Texas, drillers have to pay customers to take the stuff — or put another way, prices are negative!

Why it matters: It's surprising given that we're in the middle of the worst energy shock in history.

• But unlike oil, which trades in a global market, natural gas still mostly trades at the regional level. And the U.S. produces enough to supply itself.

The big picture: The negative price tag is an indication of just how well-positioned the U.S. is when it comes to coping with the energy shock of the Iran war — particularly in the natural gas market.

• The natural gas bounty not only insulates the U.S. from the war shock, but actually creates an economic tailwind, Bloomberg reports.

Between the lines: While prices at the pump get a lot of attention, and rightly so, natural gas is increasingly important. It now accounts for about 40% of all U.S. electricity generation — and is powering the AI boom.

Zoom in: The glut of natural gas in West Texas stems from a surge in production over the past 15 years that has far outpaced the pipelines needed to move it out of the region.

• This isn't the first time the price has turned negative.

What they're saying: That will "provide incremental takeaway capacity for a basin awash in molecules," says Chris Louney, a commodity strategist at RBC Capital Markets.

• But "the basin is prolific, and associated gas will continue to be produced, often in excess, alongside crude oil."

By the numbers: U.S. natural gas prices outside of the region are still positive — the benchmark Henry Hub natural gas price is sitting at $2.64 per million BTUs, down about 20% from last year.

• That's much lower than for Asia and Europe, both of which depend on imports through the Strait of Hormuz. The benchmark gas price is up about 47% in the EU and more than 50% in Asia from last year.
• Asian countries, outside of China, are grappling with a shortage that's led to rationing and severe measures to deal with shortfalls and high prices.

What to watch: The market has been becoming more global, especially with the U.S. rising as the world's top exporter of liquefied natural gas.

• Still, the Iran war is exposing the limits of that interconnected system.

Gasoline prices — the stuff at the gas station — notched a new Iran war high this morning at $4.30 a gallon on average, per AAA.

• Prices are still off their 2022 highs, but the fast spike from the end of February has been head-spinning for Americans, driving consumer sentiment to new lows.

Citigroup is rolling out a new internal AI platform that lets employees create agents, tapping into top models within one secure system that can scale those agents across the firm.

Why it matters: The AI race is playing out on Wall Street as much as it is in Silicon Valley, and banks are hurrying to offer the best AI models to employees without compromising on safety.

Driving the news: Citi's new platform, called Arc, acts as a centralized "operating system" for AI agents, CTO David Griffith tells Axios.

• It lays the groundwork for the bank's biggest push into agentic AI, or the use of multiple autonomous agents to orchestrate and complete a task together. Arc will be rolled out to developers first, and there are plans to roll it out to the broader bank over time.
• 180,000 Citi employees were already using enterprise AI tools powered by top models on the back end, but Arc will link agents and use cases into one central location.
• That means employees and managers can monitor agent behavior and stop tasks if needed, which helps prevent agents from going rogue.

Zoom in: Griffith says its agents can compile portfolio data, analyze broad market trends and test scenarios.