Vaxcyte spiked 56%, closed up 31%, and still had Monday's biggest move

Monday's index gains were a megacap story. The single-stock moves were not. Here is what moved and, as far as the filings and the reporting show, why.

Vaxcyte: the whole trial read out clean

Vaxcyte announced positive topline results from OPUS-1, the pivotal adult Phase 3 trial of VAX-31, its 31-valent pneumococcal conjugate vaccine candidate. Per the company's release filed with the SEC, VAX-31 met all prespecified co-primary immunogenicity endpoints in adults aged 50 and over. All 28 VAX-31 serotypes shared with PCV20 or PCV21 cleared the prespecified noninferiority criterion, a lower bound of the 95% confidence interval above 0.667. The three serotypes unique to VAX-31, plus cross-reactive serotype 20B, met the superiority criterion of a lower bound above 2.0 with multiplicity adjustment.

The comparators are the two vaccines already on the market: Pfizer's Prevnar 20 and Merck's Capvaxive. Against PCV20, VAX-31 met noninferiority on 20 of 20 shared serotypes. Against PCV21 it met it on 17 of 19; serotypes 3 and 12F missed the 0.667 threshold and cleared a historical 0.5 threshold instead. The trial dosed 4,047 participants at roughly 30 U.S. sites, 3,572 of them aged 50 and older and 475 aged 18 to 49, with immune responses measured one month after vaccination and safety followed for six.

The stock's day was almost as interesting as the data. StreetInsider had shares up 50% in the morning. Benzinga logged an intraday print of $87.97, up 55.7%. By the close, Vaxcyte finished at $73.82, up 30.7%. The company said results from OPUS-2 and OPUS-3 are expected in the first half of 2027 and would support a Biologics License Application submission in the first half of 2028, subject to FDA review, which is a long way from Monday.

RXO: the second freight deal of the season

C.H. Robinson agreed to acquire RXO in a cash-and-stock transaction with an implied value of $5.8 billion. RXO shares closed up 22.5% at $28.65, having traded as high as $28.80 during the session per Benzinga. The buyer is one of the largest freight brokers in North America; the target was spun out of XPO in 2022 and has spent the interval consolidating brokerage capacity of its own.

It was not the only deal in the tape. PTC closed up 33.5% at $192.26, the best performer in the S&P 500, after agreeing on Monday to be acquired by Schneider Electric for $205 a share in cash, a transaction valued at about $22.6 billion. Schneider's own shares fell on the news in Paris, a split reaction that is ordinary in large all-cash acquisitions and was sharp enough here to drag on the French market.

Sphere Entertainment: one downgrade, 13.6%

Sphere Entertainment closed down 13.6% at $110.80 after Craig-Hallum Capital cut the stock to hold from buy, according to StreetAccount. The firm's stated reason was demand for the venue's 'The Wizard of Oz' production softening faster than it had anticipated, which it said puts consensus estimates for the second half of 2026 and the first half of 2027 at risk. A single-attraction venue carries single-attraction risk, and Monday was a reminder of what that looks like when an analyst puts a number on it.

Also lower: Millrose Properties and Lennar both fell roughly 6% in midday trade, per CNBC, after Hunterbrook Media published a report on Friday questioning the economics of Millrose's single-family rental investments and the degree of Lennar's influence over the company's strategy.

Musk, TSMC and the Terafab question

Elon Musk confirmed discussions with Taiwan Semiconductor Manufacturing about helping his Terafab chip venture operate its Texas factories. Taiwan Semiconductor closed up 2.75% at $485.80. SpaceX, which listed publicly in June, rose about 6% intraday; Nasdaq market data cited by MarketSpeaker showed it at $168.31 at 11:06 a.m. Eastern, up 5.88%, which on the roughly 13.18 billion shares disclosed in its latest quarterly filing implies an equity value near $2.22 trillion.

Intel, which is also participating in the Terafab project, went the other way and closed down 2.63% at $116.19. The read-through the market seems to have made is that an outside foundry partner running the fabs is better news for the foundry than for the other participant.

Cerebras Systems rose 7.7% intraday, per Benzinga, after OpenAI chief executive Sam Altman wrote on social media that 'Cerebras is a close partner.'

The storage bounce-back

Western Digital and Seagate both rebounded after double-digit percentage losses on Friday. Markets Insider's closing table had Western Digital up 6.34% at $441.64 and Seagate up 4.49% at $887.09; Benzinga's intraday figures were higher. Both had closed down more than 10% in the previous session, so this was a partial recovery rather than new ground.

Elsewhere in the S&P 500's closing gainers, per Markets Insider: Illumina up 7.56% at $293.69, Charles River Laboratories up 7.09% at $310.77, Moderna up 6.95% at $203.21, AppLovin up 5.13%, Global Payments up 4.85%, Nucor up 4.58% and Autodesk up 4.51%.

Figures above are Monday's closing prices unless marked as intraday or midday. Intraday quotes and closing quotes frequently disagree by a wide margin on a volatile day, as Vaxcyte demonstrated. This article is informational and is not a recommendation to buy or sell anything.