(The opinions expressed here are those of the authors.)

By Anna Szymanski

June 26 (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. WHAT GOES UP ...

ANNA SZYMANSKI, ROI Editor in Charge: South Korea's KOSPI may be

down roughly 7% this week, but the chip-heavy index still

managed a monstrous 66% gain for the quarter, the best since

1998, and has roughly doubled since the start of the year. Will

this week's ructions prove to be a turning point or a speed

bump? Recent history suggests the latter.

2. GRID UNDER HEAT

GAVIN MAGUIRE, ROI Global Energy Transition Columnist:

Britain's power prices are being closely tracked as record high

temperatures strain the country's grids and disrupt daily life.

Wholesale prices have jumped to twice their average for 2026 so

far, as demand for cooling systems surges just as power

suppliers are forced to reduce output to avoid outages. To learn

more, here's a guide to track the heat wave's impact on power

systems throughout the UK and Europe.

3. HOW STICKY IS STICKY?

MIKE DOLAN, ROI Finance & Markets Columnist: U.S. inflation

picked up again in May and remains stubbornly above the Federal

Reserve's target. Even new Federal Reserve boss Kevin Warsh's

preferred trimmed-mean measure, which strips out extreme monthly

price moves, is edging toward 3%. But with crude prices now back

near pre-Iran war levels, June inflation data will be closely

watched for signs that underlying price pressures are easing

alongside energy costs. To complicate matters, there are growing

questions about whether lower prices at the pump could actually

make overall inflation worse.

4. RETHINKING THE NORTH SEA

RON BOUSSO, ROI Energy Columnist: The latest bout of political

turmoil in Britain comes as energy security has moved front and

centre following the Iran war, offering the next prime minister

a chance to rethink the country's strategy restricting North Sea

oil and gas activity.

5. AFRICA'S MINERAL MUSCLE

ANDY HOME, ROI Metals Columnist: China's imports of cobalt from

the Democratic Republic of Congo collapsed after the imposition

of export restrictions. This speaks to a broader trend of

African countries seeking to reap greater rewards from their

critical mineral wealth.

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.

(By Anna Szymanski

Editing by Marguerita Choy)