Vistra Corp. (VST) Stock Drops at the Close, Then Rebounds After Hours on PJM Auction News — What to Know Before the Market Opens Dec. 18, 2025

Vistra Corp. (NYSE: VST) ended Wednesday, December 17, 2025, with a sharp regular-session selloff — then clawed back some ground in after-hours trading as investors digested a major catalyst tied to U.S. grid capacity pricing.

By the closing bell, VST finished at $159.97, down 7.77%, after trading in a wide range that saw the stock touch $175.14 intraday and as low as $158.71, with about 6.58 million shares changing hands. ^[1]

But after the bell, sentiment improved. In extended trading, VST was quoted around $163.21 (+2.03%) as of 7:58 p.m. ET, reflecting a rebound that followed late-day headlines from the PJM Interconnection capacity auction. ^[2]

Below is what moved Vistra stock today — and what traders and investors should keep on their radar before U.S. markets open Thursday, December 18.

VST stock today: the key numbers from Dec. 17, 2025

Vistra’s Wednesday session was defined by volatility:

Close: $159.97 (-7.77%) ^[3]
Open: $174.01 ^[4]
Day high / low: $175.14 / $158.71 ^[5]
Volume: ~6.58M shares ^[6]
After hours (later evening quote): $163.21 (+2.03%) at 7:58 p.m. ET ^[7]

The whipsaw action matters because it shows two competing narratives colliding in real time:

the market’s near-term jitters around the “AI power trade”, and
a very real, very quantifiable tailwind from record-high PJM capacity prices that benefit generators with exposure to that market — including Vistra.

Why Vistra stock fell during the regular session

1) “AI power trade” volatility hit the whole group

Vistra has been trading as part of a broader basket of power and infrastructure names linked to the idea that AI data centers will drive electricity demand higher. When that theme gets questioned, the selling often spreads quickly.

A Barron’s report describing Wednesday’s selloff in GE Vernova framed the move as AI-related jitters that spilled over into other names — explicitly including Vistra alongside Constellation Energy and other AI-power beneficiaries. ^[8]

The important takeaway for VST holders: even when a company-specific story remains intact, Vistra can still move sharply if the market reprices the “AI-driven power demand” narrative.

2) Analyst target cut headlines added to caution

Another pressure point this week has been incremental softening in analyst targets after a very strong run in the stock.

On Tuesday, JPMorgan lowered its price target on Vistra to $233 from $249 while maintaining an Overweight rating, according to a TheFly note carried by TipRanks. ^[9]

A single target cut doesn’t “explain” a 7%+ down day by itself — but in a momentum-heavy name, these headlines can act like a spark when the sector tape turns risk-off.

After the bell: PJM capacity auction results push VST higher in extended trading

The most consequential late-day development was the PJM Interconnection capacity auction for the 2027/2028 planning year — with results posted after 4 p.m. ET, per PJM’s own auction schedule communication. ^[10]

PJM capacity prices hit a new record — and they’re capped at the ceiling

Reuters reported Wednesday night that PJM’s latest auction cleared at $333.44 per megawatt-day, a fresh record driven by electricity demand growth — especially from data centers — outpacing available supply. Reuters also reported PJM’s auction came up about 6,600 MW short of its reliability requirement. ^[11]

Barron’s characterized the clearing level as the highest allowable price and highlighted the political and reliability tension embedded in the result: big payments to generators, but rising consumer bills and reliability concerns that can trigger pushback. ^[12]

What Vistra announced: 10,566 MW cleared at $333.44/MW-day

Vistra filed an 8-K stating it cleared approximately 10,566 MW in the PJM capacity auction for planning year 2027/2028, at a weighted average clearing price of $333.44 per MW-day. ^[13]

That filing includes a zone-by-zone breakdown and confirms the total cleared amount (10,566.1 MW). ^[14]

Market reaction: VST bounced after hours

In the same Reuters report, the newswire noted that in after-hours trading, Vistra shares were higher (about +1.6%), alongside other PJM-exposed generators. ^[15]

Later in the evening, StockAnalysis data showed Vistra around $163.21 (+2.03%) after hours. ^[16]

Why the PJM auction matters for Vistra — and the risks investors can’t ignore

The bullish part: multi-year revenue visibility (with a big price signal)

Capacity auctions are designed to pay power suppliers for being available in the future, and the 2027/2028 price level is a strong signal that PJM believes it needs more supply to maintain reliability.

For Vistra specifically, clearing 10,566 MW at the $333.44/MW-day price point gives the market another data point supporting the idea that tight power markets can translate into meaningful cash-flow visibility for established generators. ^[17]

The bear case: politics and regulation can follow windfall pricing

Record capacity prices don’t happen in a vacuum. Reuters emphasized the consumer impact and noted that governors in PJM states have pushed for continued price limits to protect ratepayers, following a negotiated ceiling/floor structure that has been in place. ^[18]

Barron’s also pointed to the risk that rising bills and reliability worries can lead to political pressure to curb capacity payments — a real overhang for PJM-exposed generators if the policy response tightens. ^[19]

Bottom line: the auction result is a fundamental positive for many generators, but it also raises the odds of headline-driven volatility as regulators, politicians, consumer advocates, and grid stakeholders respond.

Forecasts and analyst outlook: where Wall Street sees VST heading

Despite the day’s drawdown, many analyst models remain constructive:

StockAnalysis lists 11 analysts covering Vistra with a consensus “Buy” rating and an average price target of $232.73 (with a $203 low and $256 high). ^[20]
That same dataset reflects JPMorgan’s latest move: $249 → $233 while maintaining a Buy/Overweight-style stance. ^[21]

Meanwhile, valuation-focused commentary remains split. A Simply Wall St analysis published today underscored just how dramatic Vistra’s multi-year run has been — reporting gains of 659% over three years and 962% over five years — while arguing that investors are reassessing how much future growth is already priced in. ^[22]

That divergence is exactly why VST can trade like a utility one day and like a high-beta AI proxy the next.

What to watch before the market opens Thursday, Dec. 18, 2025

Here are the most actionable items to monitor heading into the next session:

1) Pre-market follow-through on PJM auction headlines

If pre-market buyers continue leaning into the PJM result, watch whether strength broadens across PJM-exposed peers (the same “basket” often trades together). Reuters reported after-hours strength in multiple PJM names immediately after the results. ^[23]

Also watch for:

follow-up commentary from PJM stakeholders
any statements around extending or modifying price limits (a risk Reuters flagged) ^[24]

2) CPI and other 8:30 a.m. ET macro data could move rates — and utilities

Thursday morning has a heavy macro calendar. Investing.com flagged 8:30 a.m. ET releases including CPI, Core CPI, Initial Jobless Claims, and the Philadelphia Fed Manufacturing Index. ^[25]

And importantly, the Bureau of Labor Statistics noted it will publish the November 2025 CPI news release on December 18, 2025 due to revised schedules following a lapse in appropriations. ^[26]

Why it matters for VST:

Hotter inflation data can push yields higher and pressure equity multiples broadly.
Cooler inflation can revive risk appetite — but may also revive questions about the pace of demand growth if markets interpret it as a slowdown signal.

3) Watch the “AI power trade” narrative for another headline-driven swing

Barron’s reporting shows how quickly this theme can whipsaw: AI-related concerns weighed on a range of power and infrastructure names, including Vistra. ^[27]

If the market mood turns risk-off again, VST can get pulled down even if company-specific fundamentals look unchanged.

4) Practical trading reality: after-hours prices can fade at the open

Vistra’s after-hours bounce (roughly +1.6% to +2% depending on the timestamp and data source) is meaningful — but extended-hours liquidity is thinner, and pricing can reset quickly once regular trading resumes. ^[28]

A simple level-based framework many traders will watch (based on today’s tape):

Support zone: around today’s low near $158–$160 ^[29]
Near-term resistance: the mid-$160s and the prior close area near the low-$170s

The setup for Dec. 18: a tug-of-war between fundamentals and sentiment

Vistra ended Dec. 17 with a clean example of what defines the stock right now:

Sentiment risk is real (AI narrative volatility + valuation sensitivity + analyst target headlines). ^[30]
Fundamental tailwinds are also real, especially in tight power markets like PJM where capacity pricing just hit another record — and Vistra cleared 10,566 MW at the $333.44/MW-day clearing price. ^[31]

Going into Thursday’s open, the market is likely to focus on whether the PJM-driven after-hours rebound can hold — and whether CPI at 8:30 a.m. ET changes the risk backdrop for the entire tape. ^[32]