For decades, US government debt has been the closest thing markets have to a sure bet: lend Washington money, get it back. This week that certainty wobbled, as long-term borrowing costs jumped to levels last seen before the 2008 financial crisis. On Wednesday, Treasury Secretary Scott Bessent said Washington would at least double its buybacks of longer-dated bonds to calm the bond market.

Equities. Wall Street fell most of the week before a Friday rally trimmed the damage, leaving the S&P 500 down 1.43 percent and the tech-heavy Nasdaq Composite down 2.05 percent. Walmart's results captured the mood: a profit beat and raised guidance on Thursday, then a 9 percent share drop the next day.

What does it mean? Walmart's drop looks contradictory until you see why: it plans to spend its tariff-refund windfall on price cuts for shoppers rather than keep it as profit, good for households but a drag on near-term earnings. The wider weakness shared the bond market's cause: rising long-term borrowing costs make future profits worth less today, hitting technology stocks hardest.

Rates and credit. Long-term borrowing costs rose sharply while short-term rates held steady, steepening the yield curve. The 10-year US Treasury yield, which helps set mortgage rates, climbed toward 4.74 percent, its highest in about 20 months, and the 30-year touched 5.27 percent, unseen since before the financial crisis.

What does it mean? Yields rise when lenders demand more compensation to lock up money for decades, as investors priced in heavier borrowing and inflation risk. A buyback works like a government becoming its own buyer, propping up prices to cap yields, and it worked. Corporate borrowing costs barely moved, a sign this is a government-debt worry, not a company one.

Currencies. The dollar weakened against nearly every major currency. The euro rose to around 1.1678, the pound jumped to a six-month high near 1.3648, and the Swiss franc, a traditional refuge, held near its strongest levels of the year. The yen was the exception, pinned near 158.94, while China's yuan notched an eighth straight weekly gain.

What does it mean? A currency usually softens when its own government's bonds look less dependable, since investors selling bonds often sell the currency too, like this week.

Commodities. Brent crude rose toward USD 94 a barrel, a second straight weekly gain of about 6 percent, while US crude traded near USD 87. Gold pushed above USD 4,500 an ounce for a third straight weekly rise, and copper, vital to power grids and data centers, is now up nearly half over the past year.

What does it mean? Gold rises when confidence in paper currencies and government debt wavers, exactly this week's anxiety. Oil's gain reflects tighter supply, which matters for households at the pump. Copper's climb reflects longer-term demand for grids and computing power, not one week's headlines.

The week ahead: what will investors be watching? Central bankers gather in Wyoming for the Jackson Hole symposium, Thursday through Saturday, where Kevin Warsh, still an unknown quantity since becoming Federal Reserve chair in May after the narrowest Senate confirmation in the role's history, gives his first keynote as chair on Friday. His speech will be combed for any signal on how he sees the long-term borrowing costs that unsettled markets this week, since a Fed viewed as soft on inflation would only push those rates higher still.

Nvidia reports earnings Wednesday, a bellwether for the artificial intelligence spending boom behind much of this year's stock gains, and a hint of whether that boom still has momentum.