SharespectiveWall street, before your first coffee

Thu 20 Aug 2026 Issue 231

Washington's Two Minds Plus: a cancer vaccine trial worked, and Moderna nearly tripled in a day.

Good morning, and welcome to Thursday. The 30-year US Treasury bond spent Tuesday at its highest yield since 2007, which usually ends badly for shares. On Wednesday the Treasury Department said it would at least double the size of its bond buybacks. Yields fell, and Wall Street snapped a three-day losing run — the S&P 500 up 0.21%, the Nasdaq Composite up 0.16%, the Dow up 0.22%.

Three hours later the Federal Reserve published minutes showing officials arguing about whether to put rates up. And then a drug company most people had stopped thinking about in 2022 rose 177% in a session and stole the day from both of them.

Market snapshot

US levels are Wednesday's official 4​pm New York close. The NZX 50 and ASX 200 are Wednesday's local closes, taken before Wall Street opened; currencies late in Wednesday's US trading.

The Treasury put a bid under the bond market, then the Fed's minutes pulled the other way

The US Treasury said on Wednesday it will at least double the maximum size of its debt buybacks, from US$2 billion to at least US$4 billion, in the 10-to-20-year and 20-to-30-year parts of the curve, starting 9 September. The 30-year yield fell 9 basis points to 5.196%, a day after touching its highest since 2007, and the 10-year eased about 6 points to 4.647%. Shares took the hint.

What a buyback actually does. The Treasury buys back older bonds that have stopped trading much, paying with money raised elsewhere — mostly short-term bills. It doesn't reduce the debt by a cent. It puts a reliable buyer into the thinnest corner of the world's most important market, so dealers are readier to hold inventory. Secretary Scott Bessent billed it as liquidity support. It is also a government that watched borrowing costs climb for a fortnight and decided to do something.

Then at 2​pm the July minutes landed and complicated things. The Fed held at 3.50%–3.75% on a 9–3 vote, with Beth Hammack, Neel Kashkari and Lorie Logan all wanting a quarter-point rise, and the hawkishness ran wider than the three dissents. Several participants favoured an immediate increase, saying price rises looked broad based, and some thought financial conditions might not be tight enough to get inflation back to 2%. Gold rose more than 3% to its highest since early June, which is not what you get when everyone believes the problem has been solved.

Moderna nearly tripled after its cancer vaccine cleared a late-stage trial

Moderna closed at US$174.38, up 176.97% from Tuesday's US$62.96 — comfortably the biggest day in the company's listed life. Merck, its partner on the programme, rose 12.6% to US$152.20, and health care was the strongest corner of the S&P 500 on a day when tech went nowhere. The news: intismeran autogene, given alongside Merck's Keytruda, slowed the return of melanoma in patients whose tumours had been surgically removed, and slowed its spread elsewhere in the body.

How a personalised vaccine works. A patient's tumour is sequenced, the mutations that make it distinctive are identified, and a bespoke mRNA vaccine is made to teach that individual's immune system what to hunt. It is a different product for every person who gets it. The trial, INTerpath-001, ran 1,137 patients against Keytruda alone, and the companies say it is the first positive Phase 3 result for any mRNA cancer treatment.

There is a large asterisk. The companies released the conclusion and not the data — no effect size, no survival curves, nothing beyond "statistically significant and clinically meaningful", with detail promised at a medical meeting later. The share move also had a mechanical engine under it: 13.5% of Moderna's free float was sold short, and analytics firm Ortex put the day's damage to those positions at roughly US$4.8 billion, each shorted share down close to US$100. Forced buying by people covering losing bets does not care what the p-value was.

Trump paused a 50% tariff on Canada hours before it started, and called it a deal

Roughly US$20 billion of Canadian imports — electronics, sports gear, essential oils, dairy, wine and other alcohol — were due to be hit with a 50% tariff from Wednesday morning. Late the night before, Trump posted that he had paused it for three days because the two countries had a deal, subject to paperwork. US Trade Representative Jamieson Greer said it would cover market access for American goods, economic security commitments and digital trade alignment. Prime Minister Mark Carney said substantial progress had been made, with important work still to be done.

Why only three days. A pause that short is a countdown with a friendlier name: the threat stays loaded while lawyers turn a handshake into text, and the deadline does the negotiating. The cost of failure is why it works. TD Economics reckons the tariffs would knock 0.3 to 0.6 percentage points off Canadian GDP growth a year, and 77% of exporters in the affected categories expected to lose revenue.

For readers here the interest is the method rather than Canada, because New Zealand and Australian exporters have spent the year inside the same process. A number gets announced, a deadline gets set, and something smaller gets paid. That is little comfort when you are trying to price beef or wine six months out.

Newsworthy numbers

Worth a read

Wrapping up

No central bank decisions this week. The next Fed meeting is 16 September, with futures pricing roughly a 65% chance of a hold and about 30% odds of a rise, and Wednesday's minutes did nothing to settle it. Jackson Hole runs 27–29 August, where Kevin Warsh gives his first keynote as chair on the Friday morning, on financial innovation and payments. The RBNZ's next Monetary Policy Statement is Wednesday 2 September, with the OCR at 2.50% after July's hike and some economists looking for more.

Walmart reports before the US open on Thursday, having guided to constant-currency sales growth of 4% to 5% and adjusted earnings of US$0.72 to US$0.74 a share — the line to find is how much tariff cost it has passed to shoppers. Nvidia lands on 26 August after the close, data centre revenue under the microscope. In Australia, the ABS publishes July labour force figures today at 11.30​am AEST.

Both the kiwi and the Aussie had a good night, USD/NZD falling to 1.6848 and USD/AUD to 1.4035, leaving the New Zealand dollar near 59.4 US cents and the Australian dollar around 71.3. A softer US dollar as long yields came down did most of the work, helped on the kiwi's side by expectations the RBNZ has more tightening ahead.

That's Thursday. Back tomorrow.