Moderna, not a chip company

The second-best S&P 500 stock of 2026 is not a chip company. It is Moderna, and a cancer vaccine is why.

A seven-card deck on Moderna. Card 1 ranks the best S&P 500 stocks of 2026 as bars - SanDisk up 574%, Moderna 388%, Dell 248%, Micron 229%, Seagate 193% and Marvell 163% - with Moderna highlighted in green as the only one that is not a hardware company. Card 2 shows the Moderna and Merck logos above a note that up to 34 mutations are read from one patient's tumour, leading to one vaccine only that patient can use. Card 3 shows 112,000, the Americans newly diagnosed with invasive melanoma each year, with a note that only the later stages were in the trial. Card 4 sets Merck's $250m payment in October 2022 against the 50/50 split of costs and profits. Card 5 is a line chart of Moderna's share price from 2021 to now, marked at the $484 COVID peak, at $63 the day before the result and at $133 after it. Card 6 lists four unknowns: survival, effect size, approval and price. Card 7 closes on the claim that building the vaccine for everybody else is the unsolved part.

Numbers as of 21 Aug 2026

Eight of this year's ten best S&P 500 stocks sell the same thing: memory, drives and servers for AI data centres. Second place does not. Moderna is up about 388%.

What happened on 19 August: Merck and Moderna said a final-stage trial worked. This is not a normal drug. Doctors cut out the melanoma, read the mutations in that tumour - up to 34 - and build a vaccine from them for that one patient. It is given with Merck's Keytruda. In 1,137 patients it beat Keytruda on its own.

No mRNA cancer treatment had ever passed a final-stage trial before.

The scale problem is the interesting part. About 112,000 Americans are newly diagnosed with invasive melanoma each year. Not all of them would qualify - the trial took the later stages, after surgery - but every patient who does needs a vaccine built from their own tumour. Nobody has said what that will cost.

Merck paid Moderna $250m in October 2022 to join, and they split costs and profits equally. Only Moderna jumped, because only Moderna is small: the shares were $484 at the 2021 peak and $63 the day before the news. They are $133 now.

Still unknown: how much longer patients live, how big the benefit is, whether a regulator clears it, and the price.