The opinions expressed here are those of the author.

By Anna Szymanski

July 10 (Reuters) - Every Friday, Reuters Open Interest (ROI) distills the financial week into five key charts, spotlighting the major trends, surprises and overlooked moves that defined the past five days.

1. CRUDE SHRUG

RON BOUSSO, ROI Energy Columnist: Oil prices jumped this week after the latest, and most serious, flare-up in the Middle East after Iranian forces hit tankers crossing the Strait of Hormuz, prompting tit-for-tat exchanges with the U.S. However, crude prices LCOc1 remain well below $80 a barrel, indicating that traders don't think the interim peace deal between the U.S. and Iran is truly "over."

But even if this latest rise in Middle East tensions soon dies down, the stop-start flow of tankers through the Strait of Hormuz remains a nightmare scenario for Gulf nations desperate to return to normal after a bruising multi-month conflict.

2. KOSPI VOLATILITY

ANNA SZYMANSKI, ROI Editor-in-Charge: South Korea's benchmark stock index - one of the star performers of 2026 - has been particularly volatile this week, sliding more than 5% on Wednesday and briefly entering technical bear-market territory after a roughly 20% fall from a June 22 record close, before rising on Thursday and Friday.

Does this mean investors are anxious about the AI trade or the Korean companies at the heart of it? Not necessarily. The KOSPI .KS11 is still up more than 70% on the year, and Samsung 005930.KS - one of the index's main constituents - reported an eye-popping 19-fold jump in second-quarter profit on Tuesday. Sure, some investors may be getting skittish about the durability of the current AI chip boom, but we may also simply be seeing profit-taking and rotation.

In a world of rapidly changing technology, geopolitical ructions, and widespread momentum trading, market-watchers may just need to get used to seeing massive short-term moves - and not seek to overinterpret them.

3. RUSSIA'S FUEL CRISIS

MIKE DOLAN, ROI Finance & Markets Columnist: Russia remains one of the world's largest energy producers despite stiff Western sanctions following the country's full-scale invasion of Ukraine in 2022. It was therefore surprising to hear that Russians are now running short of fuel. Ukrainian drone attacks on Russia's energy infrastructure have led to rationing, rising costs and growing public discontent, with the country now having to import fuel from India and Kazakhstan.

Importantly, this led Moscow to announce on Wednesday that it was banning exports of diesel as part of its efforts to support the domestic fuel market. Russia remains a large player in diesel, so this decision could have wide-ranging implications for energy markets.

4. PARTING COMPANY

ANNA SZYMANSKI, ROI Editor-in-Charge: Short-dated U.S. bond yields remained elevated in recent months even as oil prices fell. This may indicate that markets believe inflation in the U.S. could remain sticky, even if energy prices sustainably return to levels seen before the U.S.-Iran war broke out. Core PCE, which excludes food and energy, rose 3.4% year-on-year in May, well above the Fed's 2% target. Moreover, the minutes from the Federal Reserve's June meeting, released on Wednesday, indicate that inflation fears extend beyond fuel prices to other areas, including the impact of booming AI investment on the U.S. economy.

5. ELECTRIC SHOCK

GAVIN MAGUIRE, ROI Global Energy Transition Columnist: Legislation signed by U.S. President Trump, which went into effect on July 4, accelerates the phase-out of federal tax credits for ​wind and solar projects, marking a sharp reversal from the incentives created under the Inflation Reduction Act.

This is likely to result in a drop in new energy production and a further rise in average electricity prices. Residential electricity prices, which are the highest among all major U.S. consumer groups, have already climbed by close to 40% since 2020, while prices for commercial and industrial users have also gained more than a third over that period.

Opinions expressed are those of the authors. They do not reflect the views of Reuters News, which, under the Trust Principles, is committed to integrity, independence, and freedom from bias.