Europe's main indices opened basically flat and stuck near three-week lows this morning. The driver is simple: fresh US-Iran economic threats are keeping traders from taking real risk.

Why the flat open happened

Geopolitical tension raises the chance of wider sanctions or supply disruptions. That uncertainty makes investors pull back from equities and hold more cash or safe assets. The effect spilled straight from weaker Asian trading and soft US futures into the European session, so the risk-on mood stayed muted even though crude oil prices dipped briefly and gave a little support.

Who feels it most

Banks, autos, luxury goods and other cyclical names in the DAX, CAC and FTSE tend to lag when risk appetite shrinks. Defensive sectors such as utilities, staples and pharma hold up better because they don't need strong economic growth to deliver earnings. A sustained pullback in oil also limits any quick relief for energy names while giving a minor tailwind to transport and airline stocks that use a lot of fuel.

What would change the picture

A clear step back from new sanctions or a credible de-escalation signal on either the Iran or trade-policy front would likely let risk appetite return quickly. Until then the market is pricing in caution rather than any big directional bet.