Demand among artificial intelligence companies stole the show when it came to the national office market's recovery this year, as the industry's blockbuster deals helped reshape post-pandemic leasing dynamics.

It's not the first time the technology sector has been at the forefront of an office dealmaking rebound, after firms like Google and IBM helped the nation's real estate recover in previous downturns.

But this time, technology companies involved in the creation of AI-fueled products — from language models to chips powering data centers — are standing out from their predecessors, setting the stage for growth in 2026 and moving the needle on the nation's record-high vacancy rate.

"There are a few things that make AI a bit different from old-guard tech companies, mainly in that they came out with an office-first model that has never wavered," Mark Lammas, the president of West Coast-focused landlord Hudson Pacific Properties, told CoStar News. "Tech is coming back, for sure."

That model has served as a catalyst for leasing momentum as tech companies race to scoop up the space they know is necessary to house their ambitious growth plans.

AI tenants are seeking properties that can support their "ambitious expansion plans and avoid constraints on future growth," according to Nigel Hughes, a senior director of market analytics for CoStar. Tenant demand is approaching historic highs in San Francisco, where AI leasing activity is outpacing that of other major markets across the country. Still, average lease sizes in the city are about 19% smaller than pre-pandemic levels.

That could change as more firms expand amid surging demand for artificial intelligence.

“What we’re seeing in the AI-driven office market is a clear shift in demand from 3,000 to 5,000 square foot requirements to 15,000 to 20,000 square feet as firms mature, secure additional funding and grow," Transwestern's Mike McCarthy, who helped represent landlord Clarion Partners in a deal with Recall.ai, said in a statement.

What started in the San Francisco Bay Area has rapidly expanded to cities across the country, many of which had been struggling to remedy record-high vacancy rates and are now benefiting from a procession of high-profile deals as AI tenants race to accommodate their staggering growth spurts.

Occupancy across the nation's office properties is growing at the highest levels since mid-2019, according to CoStar. That's in part due to strong dealmaking activity, with the technology sector representing roughly one-fifth of all office leases signed this year, according to CBRE.

Here's a look at how internal growth among artificial intelligence companies fueled some of the most notable office deals of the year.

Company's valuation in early 2025: About $3.4 trillion

Company's valuation in late December: About $4.5 trillion

Where: The company, which ended the year with a stock market value that's more than $1 trillion higher than at the start of the year, has leased and purchased space across the country in cities such as San Francisco, California, Austin, Texas, and Beaverton, Oregon, and is scouting potential locations in Washington, D.C.

How much: The chipmaking giant recently signed a roughly 45,125-square-foot deal to establish its first office in San Francisco in the new Mission Rock development.

Why it matters: The San Francisco lease has been one of a growing handful of investments the company has made to stretch its office real estate portfolio over the past year. This year, it became the first company in history to reach a stock market value of $4 trillion, beating out rivals such as Apple and Microsoft that have previously held the title of the world's most valuable corporation. The company has told investors it expects the AI boom to keep gaining steam in the coming years, estimating that global AI infrastructure spending on real estate and other support systems will total as much as $4 trillion by the end of the decade.

Company's valuation at start of 2025: About $62 billion

Company's valuation in late December: About $134 billion

Where: Sunnyvale, California

How much: More than 338,250 square feet

Why it matters: The data analytics and machine learning provider leased the entirety of the building at 200 W. Washington Ave. in the Silicon Valley suburb's Cityline Sunnyvale district, extending a real estate streak that has resulted in a significant boost to the company's Bay Area real estate portfolio. The deal, signed this summer, came right on the heels of a 150,000-square-foot deal Databricks made to expand its headquarters at the One Sansome tower in San Francisco's Financial District. The company extended its leasing streak to the South Bay Area to accommodate a regional workforce that has more than doubled over the past two years, "with projections to double again over the next two."

Cofounder and Chief Architect Reynold Xin said in a statement about the lease that "this investment will accelerate our pace of research and product development, deepen our collaboration with customers, and help us attract the best minds to push the boundaries of what’s possible with data and AI."

Company's valuation at start of 2025: An estimated $300 billion

Company's valuation in late December: Estimated at more than $500 billion

Where: Bellevue, Washington

How much: About 49,000 square feet

Why it matters: While the Seattle-area deal itself is on the smaller side, the July lease underscores AI companies' trajectory in establishing primary office space in cities such as San Francisco and then extending outward. OpenAI's agreement to backfill former Microsoft space in the City Center Plaza tower in downtown Bellevue also shows shifting dynamics in terms of which tech companies are pulling back on office investments and which are stepping them up. The ChatGPT maker has rapidly expanded over the past year and now occupies more than 1 million square feet of office space in San Francisco alone, generating some of the city's largest deals since the onset of the pandemic in 2020.

Company's valuation at start of 2025: About $3 billion

Company's valuation in late December: About $8 billion

Where: San Francisco, New York

How much: The company signed a 92,663-square-foot deal to roughly double its Manhattan office presence just a few months after signing a roughly 92,000-square-foot lease to triple its San Francisco headquarters.

Why it matters: Harvey AI's real estate moves this year display the rapid-fire pace AI companies have adopted to expand their real estate portfolios. The company's Manhattan expansion, for example, was inked fewer than 12 months after it signed a deal to lease a floor at 315 Park Ave. S. in April 2024 before adding another later in the year. Harvey's expansion echoes deals that other artificial intelligence companies have made in recent years to rapidly expand their real estate footprints in an effort to bolster explosive spikes in head count, revenue and demand.

Company's valuation at start of 2025: Estimated at less than $3.5 billion

Company's valuation in late December: An estimated $61.5 billion

Where: San Francisco

How much: An estimated 400,000 square feet

Why it matters: Anthropic's plans to fill all of the more than 400,000-square-foot San Francisco tower at 300 Howard St. demonstrate how, while they may start small, the furious demand among AI companies for office space can ultimately result in deals for entire buildings. The company is in the final stages of negotiating to expand its San Francisco headquarters as it has raced to accommodate aggressive growth. Those full-building negotiations land just a few months after Anthropic added about 104,000 square feet across multiple floors at 505 Howard St. The expansion boosted the company's total footprint to roughly 335,000 square feet across San Francisco's Foundry Square office complex, where it has been headquartered for the past couple of years.