Waning optimism over Trump's deal to end the Iran war tanks stocks and sends oil surging again

Jim WATSON / AFP via Getty Images

• US stocks plunged on Thursday while oil rose as investor optimism over an Iran peace deal waned.
• Investors weighed whether Trump could secure a swift end to the war in Iran.
• Trump has successfully eased worries before, but his latest comments haven't sparked a turnaround.

US stocks tumbled and oil prices spiked on Thursday despite Donald Trump's push to bring an end to the Iran war.

Trump reiterated that talks with...