B01
Why Can the S&P 500 Rise When More Stocks Are Falling?
A few positive contributions can outweigh many smaller negative contributions in a weighted index.
Market Education / Collection
Weighted Impact & Market Intelligence
Connect market breadth, stock returns, index weight, and the contribution behind an index move.
8 topics in this collection · 3 existing full guides · 5 new drafts
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B02
What Really Moves the S&P 500?
Index movement reflects the combined weighted returns of its constituents and index calculation rules.
Full editorial draft available for owner review; not approved for public indexing.B03
A Stock Can Rise 5% and Barely Move the Index. Why?
A large percentage move from a low-weight stock can contribute less than a small move from a high-weight stock.
Full editorial draft available for owner review; not approved for public indexing.B04
What Is Weighted Index Contribution?
A simplified estimate multiplies a security's index weight by its percentage return.
B05
What Does Points per $1 Mean?
A sensitivity estimate translates a one-dollar stock-price change into approximate index points using a reference level.
B06
Market Breadth vs. Weighted Market Impact
Advancer counts and weighted contributions answer different questions about the same session.
Full editorial draft available for owner review; not approved for public indexing.B07
Why Do the Biggest Movers Differ From the Biggest Contributors?
The largest price change does not necessarily produce the largest index contribution.
Full editorial draft available for owner review; not approved for public indexing.B08
Can 10 or 30 Stocks Explain the Whole Market?
A selected basket can illuminate important drivers while still representing only part of an index.
Full editorial draft available for owner review; not approved for public indexing.