Wall Street pros are getting increasingly nervous about Iran and warning that markets may be too complacent.

Nearly a month into the conflict and the closure of the Strait of Hormuz, the S&P 500 is down about 4%, while traditional safe havens like gold and Treasurys have struggled to rally.

Oil has been far more volatile. Brent and West Texas Intermediate crude surged as much as 80% at one point to nearly $120 a barrel, though both grades have since pulled back below $100.

That relatively muted cross-asset reaction has raised concerns that investors are underestimating the potential fallout from the Middle East crisis.

Here's what top investors are saying about the market's reaction.