Oil prices tumbled Monday as optimism grew over a potential U.S.-Iran nuclear agreement. Brent crude futures plunged more than 5%, breaching the $95-a-barrel mark for the first time since April. The sell-off rippled through markets, pulling down European bond yields as inflation concerns temporarily eased and weakening the dollar.

This sharp decline reflects expectations that Iranian oil could re-enter the global market, increasing supply. However, the initial market reaction was tempered. While Dow Jones Industrial Average futures advanced, suggesting a risk-on mood, investors remain deeply skeptical about the durability of the talks and the actual timeline for any new barrels hitting the market.

The muted celebration underscores the market's caution. A final deal faces significant hurdles, and even a successful agreement would likely involve a phased return of Iranian crude. Consequently, the focus has quickly shifted from the headline drop to parsing the fine print of any potential accord and its realistic impact on global energy balances.