West Texas Intermediate crude fell 4.62 percent late Sunday after President Donald Trump told reporters aboard Air Force One that he had cancelled what he called the biggest strike on Iran since World War Two, and that a deal on the Strait of Hormuz was close. By Monday, Iranian Foreign Ministry spokesperson Esmail Baghaei said Tehran had no negotiations underway with Washington, and Trump responded on Truth Social by calling Iran's leadership unbelievably duplicitous. WTI is trading near 81.30 US dollars a barrel Tuesday morning, up roughly 1.3 percent, according to Investing.com.
Nothing about the underlying dispute changed between Sunday's plunge and Tuesday's partial recovery. What changed was which headline was most recent.
A Pattern That Has Repeated Four Times in a Month
This is not an isolated whipsaw. WTI has reversed sharply on Iran headlines at least four times since July 8, when the June 17 ceasefire memorandum collapsed and crude jumped 4.37 percent in a single session. It happened again on July 13, when the contract rose 9.14 percent on renewed conflict. It happened a third time on July 29, when Iran's rejection of an Omani proposal for joint oversight of the strait sent WTI up 6.56 percent to 84.46. Sunday's 4.62 percent drop is the fourth.
Each of these moves was traded as though it settled the question of where the war was headed. Each time, the next few sessions showed that it had not.
Why the Newest Headline Always Feels Like the Real One
The behavioural finance term for this is recency bias, a specific case of the heuristics Amos Tversky and Daniel Kahneman documented in their 1974 paper on judgment under uncertainty. Their finding was that people do not weigh new information against the full run of prior evidence. They anchor on whatever arrived most recently and adjust from there, discounting the base rate almost entirely.
Applied to this market, the base rate is now well established. A US or Iranian statement suggesting imminent resolution has arrived roughly once every two to three weeks since the ceasefire first collapsed, and every one of those statements has been followed within days by a contradiction, a denial, or a renewed threat. A trader applying that base rate to Sunday's announcement would have discounted it heavily before the market opened. Most of the market did not.
Recency bias is distinct from simple overreaction. It is not that traders misjudge the size of a single piece of news. It is that each new headline is evaluated in isolation, as though the sequence of prior headlines carries no information about how reliable this type of headline has been.
WTI's daily closes since the ceasefire collapsed trace all four reversals, including Sunday's drop and this morning's partial recovery.Each dashed marker corresponds to a single headline event. Tuesday's early session is included and may still move before the close.
What Base Rate Neglect Costs a Portfolio
Shefrin's work on behavioural portfolio management describes the practical cost of this pattern clearly. Investors who trade each new headline as a discrete, fully informative event end up buying strength and selling weakness in a tight loop, paying the spread and the tax cost of short holding periods without capturing the underlying trend either way.
The four reversals this month have not changed the physical picture in the Strait of Hormuz. Kpler's tanker tracking data shows crossings rose eight percent week over week through August 2, but daily transits still averaged only about 15, against a pre-conflict baseline in the neighbourhood of 90 to 140. That structural reality has moved slowly and steadily. The headlines have moved four times faster than the ships have.
The Gap Between the Headline and the Structural Story
None of this means Sunday's cancellation or Monday's denial should be ignored. It means each one carries less new information than its size of price move suggests, because the market has not yet adjusted its confidence in this category of headline downward to match how often it has failed to hold. A base rate of roughly four reversals in four weeks is itself a data point, and it is the one getting the least weight.