TeraWulf (WULF) spiked 18%, then gave most of it back: sell the news, buy the rumor

TeraWulf (WULF) had one of its biggest headline days ever on July 6, and the stock still could not hold the gain. A 20-year, $19 billion lease with Anthropic is about as good as news gets for a former bitcoin miner turned data center operator. The stock opened up 14%, ran to a session high of $25.04, and then spent the rest of the day giving that gain back. It closed at $22.20, up about 5% on the day instead of 18%.

This is a textbook version of an old trading line: sell the news, buy the rumor.

How the day actually traded

WULF closed Thursday, July 2, at $21.18. It opened Monday at $24.21, already pricing in a chunk of good news before the bell even rang. Within the first 15 minutes of trading it touched $25.04, its high for the day and a fresh 52-week high territory push. From there it slid most of the morning, dropping under $24 within the hour and under $23 by lunchtime. The stock never went red. It just kept handing back the morning's excitement, a few percent at a time.

Add it up and WULF gave back close to three-quarters of its opening pop by the close, without a single new piece of bad news arriving to explain it.

Why good news can still sell off

Short interest is the biggest reason. WULF is shorted at roughly 30% of its float, one of the more heavily shorted names in the AI data center trade. When news like this breaks, a chunk of that early buying comes from short sellers racing to close losing bets before they get run over. That kind of buying can create a sharp opening spike that has little to do with how the market actually feels about the deal's long-term value.

Once that forced buying dries up, the stock is left with whoever is willing to pay the new, higher price with real conviction. That group is usually smaller than the group of people just closing out a losing short. The result looks exactly like today: a violent spike, then a grind lower as the squeeze fades and the stock searches for a price that reflects the news on its own merits.

There is also the calendar. TeraWulf's Abernathy, Texas stake sale to a Fluidstack-led group and speculation about an Anthropic tie-up had been floating around before today, so some traders who positioned ahead of confirmation used the opening spike as their exit. Once a rumor becomes confirmed fact, some of the people who bought it early end up among the first sellers once the news actually lands.

The buy the rumor half of the trade

If WULF is the sell the news side, the rumor money went somewhere else entirely on July 6: IREN and SharonAI (SHAZ), both caught up in Anthropic's separate, still-undecided $15 billion Australia data center plan. IREN is one of five shortlisted bidders on that project, alongside names like AirTrunk and NextDC. SharonAI is not a bidder, but investors have been watching it closely because Leopold Aschenbrenner's fund holds a large stake in the company and Aschenbrenner has a reported personal connection to Anthropic's CEO's office. That Australia decision is not final either way, with no winner picked and a call still weeks out. None of that stopped both stocks from running hard today. IREN traded up as much as 16% intraday and closed up about 13%. SharonAI ran even further, touching a 24% intraday gain and closing up nearly 18%, clawing back almost to its high into the final minutes of trading.

Neither company signed anything today. The move looks like traders using TeraWulf's confirmed, signed Anthropic deal as proof that Anthropic is actively closing large infrastructure contracts right now, then bidding up the stocks positioned for its next one, which has not happened yet. Both names had also sold off hard into the holiday weekend before this tender report even surfaced, so part of today's run is simply unwinding that prior slide. That combination, real confirmed news pushing money into unconfirmed speculation, is about as clean a buy the rumor setup as this sector has produced in a while.

The math behind the headline number

A $19 billion contract sounds enormous next to TeraWulf's roughly $11 billion market cap, and it is real money. But it is spread across 20 years. Divide it evenly and it works out to about $950 million a year, against a company that currently loses money and does not expect first power delivery from the deal until late 2027. That is a big, credible number for a company this size. On its own, it does not justify doubling a stock in a single session, and the market spent the rest of the day pricing that difference back out.

What to watch from here

WULF closed green, which matters. A fade from an 18% intraday gain to a 5% close reads as a stock cooling off. A red close on a day with news this good would have been the far uglier signal about how the market is actually pricing the deal. For now, this looks like a short squeeze burning off while the stock searches for a fair price on real, if not miraculous, news. This is exactly the kind of name where position sizing matters more than usual. A stock that can run 18% above its prior close and then close back near 5% in the same session can turn a normal-sized position into an oversized one fast.

Sources

• Intraday and closing prices from live market data, Monday, July 6, 2026, as of the 4 p.m. ET close.
• Short interest estimated at roughly 28% to 32% of float depending on reporting date and methodology, per short-interest trackers including MarketBeat and Fintel.
• Lease and Abernathy sale terms from TeraWulf's July 6, 2026 announcement, covered in our earlier report on the deal.
• Anthropic's Australia data center tender and the Aschenbrenner fund's IREN and SharonAI stakes, covered in our earlier report on that story.

This is not investment advice. TeraWulf and short-interest data move fast and the numbers above will be stale quickly. Do your own research before trading a stock this volatile.