Oil prices fall to three-month low ahead of US-Iran agreement Oil prices have fallen sharply to their lowest levels in three months, as markets reacted positively to the anticipated signing of a formal agreement between Washington and Tehran later this week. Brent crude futures dropped $3.29, or four percent, to $79.88 a barrel, while US West Texas Intermediate crude fell $3.82, or 4.7 percent, to $76.93, according to Reuters. The decline extends losses seen earlier in the day, when oil prices had already fallen by more than two percent.