Observatory · observe first

Where is market allocation moving?

See what is gaining weight, how quickly it is changing, and what is driving the move.

Historical time machine
Historical observation
20182026
S&P 500 matched members · 122 industries · Sep 2025Market-cap weights, not measured fund flows · pp = percentage points
Gaining weight
33
industries · over the last 12 months
Losing weight
78
industries · over the last 12 months
Accelerating
8
positive 3M gains are speeding up
Slowing
23
3M movement is easing, in either direction

What is driving the change?

12-month company attribution · a rising industry does not mean every company is gaining

Follow the hierarchy →
Concentrated

Most of this industry's gains came from a few companies.

Nvidia+2.142 pp
All other companies+0.972 pp
50% of companies above their 6M weight average
See what contributed →
Concentrated

Most of this industry's losses came from a few companies.

Lilly (Eli)-0.514 pp
All other companies-0.502 pp
14% of companies above their 6M weight average
See what contributed →
Concentrated

Most of this industry's gains came from a few companies.

Tesla, Inc.+0.926 pp
All other companies-0.004 pp
100% of companies above their 6M weight average
See what contributed →

Industry movements at a glance

Largest absolute allocation changes · descriptive observations, not rankings of investment merit

Watch the historical rotation →
IndustryMarket weight12M changeMovementParticipationWeight history · 24M
Semiconductors
Gained weight for 1 consecutive month
14.71%+3.11 ppSlowingConcentrated
Pharmaceuticals
Lost weight for 1 consecutive month
3.39%-1.02 ppSlowingConcentrated
Automobile Manufacturers
Gained weight for 2 consecutive months
3.08%+0.92 ppAcceleratingConcentrated
Managed Health Care
Gained weight for 2 consecutive months
0.87%-0.85 ppSlowingConcentrated
Technology Hardware, Storage & Peripherals
Gained weight for 2 consecutive months
7.97%-0.58 ppReversing upwardConcentrated
Diversified Banks
Lost weight for 1 consecutive month
3.84%+0.53 ppSlowingConcentrated
Asset Management & Custody Banks
Lost weight for 2 consecutive months
1.45%+0.49 ppDeclining fasterConcentrated
Life Sciences Tools & Services
Lost weight for 1 consecutive month
0.91%-0.49 ppReversing upwardConcentrated
Systems Software
Lost weight for 2 consecutive months
8.28%+0.44 ppReversing downwardConcentrated
Investment Banking & Brokerage
Gained weight for 6 consecutive months
1.41%+0.40 ppSlowingConcentrated
How are these descriptive states defined?

Gaining / losing: 12-month weight change above +0.005pp / below −0.005pp. Direction and speed are separate dimensions, not mutually exclusive recommendations.

Accelerating / slowing: compare the most recent 3M change with the preceding 3M change. Accelerating means a positive change speeds up by >0.02pp. Slowing means the magnitude of movement declines by >0.02pp. A falling industry can also slow.

Reversing: the last two 3M changes have opposite signs, outside a ±0.005pp tolerance. Persistence counts consecutive same-direction monthly changes.

Broad / concentrated: company attribution, not a market-cap concentration shortcut. Concentrated means the three largest same-direction contributors account for ≥70% of gross same-direction changes; otherwise broad requires ≥60% of constituents moving with the industry. Other cases are mixed.

Weights use matched S&P 500 members with SEC-reported shares and monthly prices. Companies without both data series are omitted; weights are normalised across matched members each month. These are simple market-cap estimates, not official float-adjusted S&P weights or measured investor flows.