📊 The Deep DiveIssue #005Week of 28 June 2026 · 12 min read

H1 2026 Review — What Drove the Rally and What Comes Next

An 18.6% S&P gain hiding a 10-point gap between cap-weighted and equal-weighted returns. Three H2 scenarios. And the signals that will tell you which one is playing out.

Finance Explained Simply

The Deep Dive

Full analysis · Week of 28 June 2026 · 12 min read

H1 2026 is over. The S&P 500 is up 18.6%. AI stocks have tripled. And inflation is running at double the Fed’s target. This week we step back from the daily noise and ask the question that matters most: what does the first half tell us about the second?

In this issue

01 H1 by the numbers — what actually happened and why

02 The concentration problem — five stocks carrying the entire index

03 Why bonds had a miserable half — and what that signals

04 H2 scenarios — the bull case, the base case, and the risk case

◆ Concept of the week: Market concentration and index risk

01 — H1 2026 by the Numbers

S&P 500 Up 18.6% in the First Half. Here Is What Drove It — and What It Cost.

The S&P 500 closed the first half of 2026 at approximately 7,400 — up 18.6% from its January 1 level of around 6,240. It is the best first half since 2019, and it sits against a backdrop of inflation running at double the Fed’s target, geopolitical tension in the Middle East, and rate expectations that have moved materially more hawkish than the year began.

The driver was overwhelmingly AI. The Nasdaq Composite gained 24% in H1. Nvidia alone added over $1.2 trillion in market capitalisation. Microsoft, Alphabet, Meta, and Amazon each rose 20–40%. The equal-weighted S&P 500 (which gives every stock the same weight, regardless of size) rose only 8% over the same period. The market’s headline gain was real, but it was narrow.

H1 2026 Performance: Cap-Weighted vs Equal-Weighted

+24%

Nasdaq

+18.6%

S&P 500

+8%

S&P Equal-Wt

H1 2026 total returns · 10-percentage-point gap between cap-weighted and equal-weighted S&P reveals how concentrated the rally was

02 — H2 Scenarios

Three Possible H2 Stories — and What Would Have to Be True for Each

Bull case: Inflation falls to 3% by year-end, the Fed signals a cut in December, AI earnings upgrades continue to roll in, and geopolitical risk de-escalates. The S&P makes new highs above 8,000. Possible, but requires several things to go right simultaneously.

Base case: Inflation stays sticky at 3.5–4%, the Fed holds through H2 with a hawkish bias, equity markets churn sideways as rate expectations stay elevated, but corporate earnings hold up. S&P finishes the year at 7,200–7,600. Most strategists are in this camp.

Risk case: CPI re-accelerates above 5% (perhaps on an oil shock or wage spiral), the Fed is forced to hike at least once, and long-duration growth stocks re-rate sharply lower. The equal-weighted S&P falls 15–20%, though the headline index is cushioned by defensive megacaps. This scenario is underpriced in current options markets.

◆ Concept of the Week

Market Concentration — When Five Stocks Carry an Entire Index

The S&P 500 is a market-capitalisation-weighted index — bigger companies have bigger weights. The five largest constituents (Microsoft, Nvidia, Apple, Alphabet, Amazon) now represent over 28% of the index’s total weight. This means an S&P 500 index fund is not a diversified bet on 500 companies — it is a concentrated bet on a handful of mega-cap tech and AI names, with 495 smaller companies along for the ride. This is why the equal-weighted version of the S&P returned less than half as much in H1: most stocks did not participate in the AI-driven rally at all.

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