2026.4.21 US Stock Brief | Iran-US Talk Hopes Cool, All Three Indexes Close Lower

Prospects for Iran-US negotiations turned cold, and all three major indexes closed lower. The S&P 500 finished at 7,064.01, down 0.63%; Nasdaq at 24,259.96, down 0.59%; Dow at 49,149.38, down 0.59%. The WSJ summed up the day’s sentiment as “Markets in Wait-and-See Mode.”

The ceasefire was extended, but talks remain in limbo. Trump extended the ceasefire until Iran submits a proposal, with the WSJ headline reading “Trump Extends Iran Cease-Fire With Peace Talks in Limbo.” Polymarket’s numbers tell a more sober story: 0% probability of a permanent peace deal by April 22, 14% by April 30, and a 12% chance of the Strait of Hormuz returning to normal passage by end of April. The prediction market discounted the official optimism considerably.

The selloff itself was modest. The VIX rose 3.34% to 19.50—hedging demand quietly creeping back. Sector divergence was the more important signal of the day: Energy (XLE) gained 1.45%, with geopolitical tension pricing directly into oil and gas, even as WTI crude at $89.31 dipped 0.33%. The real damage hit rate-sensitive sectors—the 10-year Treasury yield at 4.29% dragged real estate (XLRE) down 1.93% and utilities (XLU) down 1.75%. Tech (XLK) was nearly flat at +0.08%; big money was watching, not fleeing.

Two individual stock moves stood out. UnitedHealth beat Q1 expectations, with strong earnings lifting the stock. AMD rose 3.47% and added another 1.12% after hours. Apple fell 2.52% on volume of 50.2 million shares, though leadership changes had limited impact on the price.

After-hours signals were clearer. SPY gained 0.41% and QQQ 0.49% in post-market trading. The WSJ’s evening headline leaned optimistic: “No Peace Plan, No Problem: Why the Wartime Market Keeps Rising.” But the mild after-hours bounce only indicates risk appetite didn’t deteriorate further—it doesn’t mean the narrative has flipped.

On the Fed front, Polymarket puts the probability of rates staying unchanged at the April meeting at 99%—no suspense there. Warsh faced Senate confirmation hearings on financial disclosure and Fed independence.

All three indexes dropped less than 1% on the day. The harder data points: Polymarket gives just a 14% chance of a permanent Iran-US peace deal by April 30, and only 12% for the Strait of Hormuz returning to normal by month-end. What matters more going forward is whether these two expectations continue to drift lower, and whether this week’s mega-cap earnings can sustain the AI boom narrative.