If you were looking for action in the stock market last week, you didn't have to look far. A powerful cocktail of AI hype, short squeezes, and big-ticket deals sent a bunch of large-cap stocks soaring, with some posting gains that would normally be reserved for a wild year, not a quiet week.

The theme was unmistakable: investors are still betting big on the physical backbone of the artificial intelligence revolution. Data centers, the chips that go in them, and the specialized equipment that connects them all saw massive inflows. But the rally wasn't purely technical; real news from companies about real orders and partnerships provided the fuel.

Let's break down who moved and, more importantly, why.

Topping the list was an unlikely contender: Avis Budget Group, Inc. (CAR). The rental car company's stock shot up 51.15% in what was widely described as an overheated short squeeze. When traders who bet against a stock are forced to buy it back to cover their losses, it can create a feedback loop that pushes prices into record territory—exactly what happened here.

In the more predictable realm of tech hardware, Applied Optoelectronics, Inc. (AAOI) gained 37.18%. The company gave investors a concrete reason to buy, announcing it had received a new $71 million order for its 800G single-mode data center transceivers from one of its major hyperscale customers. Not everyone was convinced, however. The short-selling firm Citron came out against Applied Optoelectronics, calling its rally overhyped even while saying it remained bullish on another fiber player, Corning.

Speaking of AI infrastructure, Nebius Group (NBIS) jumped 33.92%. The move came after a report from The Information that the AI cloud provider, which is backed by Nvidia and operates data centers in Europe and the U.S., is in talks to buy Israeli-based AI startup AI21 Labs. AI21 Labs makes natural language processing models, so a deal would beef up Nebius's AI software capabilities to go with its hardware.

Other chip and component makers rode the wave. Astera Labs, Inc. (ALAB) gained 27.6%, TTM Technologies, Inc. (TTMI) soared 25.08%, and Amkor Technology, Inc. (AMKR) increased 19.98%. These are the kinds of companies that make the specialized parts that go into servers and networking gear, and right now, demand for that stuff is through the roof.

Then there's CoreWeave, Inc. (CRWV), which jumped 25.63%. The cloud computing company specializing in AI workloads was in the news on two fronts. First, reports suggested that AI lab Anthropic had agreed to rent CoreWeave's computing power. Second, JPMorgan analyst Mark R. Murphy weighed in on CoreWeave's expanded agreement with Meta Platforms Inc. (META), calling it a significant step in scaling AI infrastructure. He did flag both upside potential and execution risks, which is analyst-speak for "this could be huge, but they have to actually pull it off."

One of the most watched moves came from the old guard: Intel Corporation (INTC) increased 22.42%. The chipmaker had a busy week signaling its ambitions in the AI space. It posted on social media that it is set to join the Terafab project, an industry consortium focused on advanced packaging technology. Perhaps more importantly, it announced a multiyear collaboration with Alphabet Inc.'s (GOOG) Google to advance the next generation of AI and cloud infrastructure. For a company trying to reinvent itself, partnerships like this are crucial.

Rounding out the list were two more names from different corners of the market. SK Telecom Co., Ltd. (SKM) soared 21.04%. Bloom Energy Corporation (BE) gained 21.18%, with Susquehanna analyst Biju Perincheril maintaining a Positive rating on the stock.

So, what's the takeaway from last week's frenzy? It's a reminder that the market's obsession with AI isn't just about software and chatbots. It's a full-blown industrial build-out. Companies that make the physical guts of data centers—the optics, the chips, the power systems, and the cloud capacity itself—are seeing orders roll in and their stocks react in kind. Whether this is a sustainable boom or another chapter in the hype cycle remains to be seen, but for one week at least, the builders were winning big.