Summit Materials, Inc. Class A (SUM)
SUM moved a median of 0.00% 30 minutes after news, and -0.10% by the close. How SUM actually reacts to news — the realized, point-in-time move the market made, measured across 276 labeled events over the last three years with zero look-ahead.
SUM’s median reaction, across the day.
| Horizon | Median | % positive | Events |
|---|---|---|---|
| 5-min | 0.00% | 46% | 247 |
| 30-min | 0.00% | 44% | 248 |
| 60-min | 0.00% | 45% | 248 |
| to close | -0.10% | 35% | 249 |
| Middle 50% of SUM reactions | -0.12% to +0.19% |
|---|---|
| Median reaction (30-min) | 0.00% |
| Measured reactions | 276 |
Half of all Summit Materials, Inc. Class A news events land between -0.12% and +0.19% at 30 minutes.
Reaction stats as of 2026-09-21. Newest measured event . Reaction = percent move vs. the price at the news timestamp.
How SUM reacts, by analyst action.
| Event | Events | Median 30-min | % positive | Median to close |
|---|---|---|---|---|
| Analyst upgrades | 12 | +0.08% | 50% | -0.01% |
| Analyst downgrades | 27 | 0.00% | 37% | +0.10% |
| Coverage initiations | 12 | +0.09% | 75% | -0.05% |
| Rating reiterations | 41 | +0.11% | 56% | +0.11% |
| Price-target raises | 14 | -0.07% | 43% | -0.10% |
Last 3 years, pulled 2026-09-21. Reaction = percent move vs. the price at the news timestamp. Counts and medians only. The same measurement runs across every name in the dataset. 1 further class was observed with fewer than 10 measured events and is not published. See how SUM ranks against every other measured name →
That’s how SUM usually reacts — get an email when it moves on news →Email me when SUM moves on news.
One email per qualifying move — the headline, the measured reaction, and how it compares to SUM's baseline. Nothing else.
Recent SUM events, each with its measured reaction.
| Date | Headline | Event | Source | 5-min | To close |
|---|---|---|---|---|---|
| Form 8-K Summit Materials, Inc. For: Feb 10 | SEC filing · Form 8-K | SEC EDGAR | — | — | |
| Form POSASR Summit Materials, Inc. | SEC filing · Form POSASR | SEC EDGAR | — | — | |
| Form S-8 POS Summit Materials, Inc. | SEC filing · Form S-8 | SEC EDGAR | — | — | |
| Summit Materials Completes Merger with Quikrete | Press release | PR Newswire | -0.01% | +0.00% | |
| Form 8-K Summit Materials, Inc. For: Feb 05 | SEC filing · Form 8-K | SEC EDGAR | -0.02% | +0.23% | |
| Summit Materials Announces Stockholder Approval of Quikrete Transaction | Press release | PR Newswire | +0.00% | -0.08% | |
| Form 8-K Summit Materials, Inc. For: Jan 28 | SEC filing · Form 8-K | SEC EDGAR | -0.10% | -0.10% | |
| Form 8-K Summit Materials, Inc. For: Jan 27 | SEC filing · Form 8-K | SEC EDGAR | -0.10% | -0.10% | |
| Form 8-K Summit Materials, Inc. For: Jan 06 | SEC filing · Form 8-K | SEC EDGAR | +0.02% | -0.17% | |
| Form DEFA14A Summit Materials, Inc. | SEC filing · Form DEFA14A | SEC EDGAR | +0.02% | -0.17% | |
| Summit Materials Announces Expiration of the Competition Act (Canada) Waiting Period for Acquisition by Quikrete | Press release | PR Newswire | +0.02% | -0.17% | |
| Form DEFA14A Summit Materials, Inc. | SEC filing · Form DEFA14A | SEC EDGAR | +0.01% | -0.12% | |
| Summit Materials Announces Expiration of HSR Act Waiting Period for Acquisition by Quikrete | Press release | PR Newswire | +1.87% | +2.13% | |
| Form DEFM14A Summit Materials, Inc. | SEC filing · Form DEFM14A | SEC EDGAR | -0.18% | -0.20% | |
| SUM Stock Alert: Halper Sadeh LLC Is Investigating Whether the Sale of Summit Materials, Inc. Is Fair to Shareholders | Press release | Business Wire | +0.06% | -0.06% | |
| Form 8-K Summit Materials, Inc. For: Dec 20 | SEC filing · Form 8-K | SEC EDGAR | +0.12% | -0.10% | |
| Form PREM14A Summit Materials, Inc. For: Dec 19 | SEC filing · Form PREM14A | SEC EDGAR | +0.24% | +0.30% | |
| BRODSKY & SMITH SHAREHOLDER UPDATE: Notifying Investors of the Following Investigations: Summit Materials, Inc. (NYSE – SUM), Entero Therapeutics, Inc. (Nasdaq - ENTO), Liberty Broadband Corporation (Nasdaq – LBRDA, LBRDK, LBRDP), Manitex International, I | Press release | GlobeNewswire | -0.02% | -0.08% | |
| BRODSKY & SMITH SHAREHOLDER UPDATE: Notifying Investors of the Following Investigations: Summit Materials, Inc. (NYSE – SUM), Entero Therapeutics, Inc. (Nasdaq - ENTO), Liberty Broadband Corporation (Nasdaq – LBRDA, LBRDK, LBRDP), Manitex International, I | Press release | GlobeNewswire | +0.03% | +0.37% | |
| Form DEFA14A Summit Materials, Inc. | SEC filing · Form DEFA14A | SEC EDGAR | +0.16% | +0.10% | |
| SUM Alert: Monsey Firm of Wohl & Fruchter Investigating Fairness of the Sale of Summit Materials to Quikrete Holdings | Press release | GlobeNewswire | -0.05% | -0.21% | |
| SUM Stock Alert: Halper Sadeh LLC Is Investigating Whether the Sale of Summit Materials, Inc. Is Fair to Shareholders | Press release | Business Wire | +0.16% | +0.10% | |
| Summit Materials Enters into Definitive Agreement to be Acquired by Quikrete for $52.50 Per Share in Cash | Press release | PR Newswire | +0.16% | +0.10% | |
| Summit Materials Responds to Media Reports | Press release | PR Newswire | -0.39% | -1.22% | |
| Form 8-K Summit Materials, Inc. For: Nov 13 | SEC filing · Form 8-K | SEC EDGAR | -0.38% | +0.27% | |
| Form 10-Q Summit Materials, Inc. For: Sep 28 | SEC filing · Form 10-Q | SEC EDGAR | -0.18% | -0.65% | |
| Form 8-K Summit Materials, Inc. For: Oct 30 | SEC filing · Form 8-K | SEC EDGAR | +0.69% | -0.53% | |
| Summit Materials, Inc. Reports Third Quarter 2024 Results | Press release | PR Newswire | +0.69% | -0.53% | |
| Summit Materials Discloses Receipt of a Non-Binding Acquisition Proposal | Press release | PR Newswire | -2.28% | -2.25% | |
| Summit Materials Announces Third Quarter 2024 Results Conference Call Date | Press release | PR Newswire | -0.49% | +1.49% | |
| Summit Materials and Green America Recycling Pioneer Alternative Fuel Technology at the Davenport, Iowa Cement Plant | Press release | PR Newswire | -0.14% | +1.78% | |
| Form 8-K Summit Materials, Inc. For: Aug 22 | SEC filing · Form 8-K | SEC EDGAR | +0.00% | +2.10% | |
| Form 10-Q Summit Materials, Inc. For: Jun 29 | SEC filing · Form 10-Q | SEC EDGAR | +0.13% | -0.65% | |
| Form 8-K Summit Materials, Inc. For: Aug 05 | SEC filing · Form 8-K | SEC EDGAR | +1.44% | +2.98% | |
| Summit Materials, Inc. Reports Second Quarter 2024 Results | Press release | PR Newswire | +1.44% | +2.98% | |
| Form 8-K Summit Materials, Inc. For: Jul 25 | SEC filing · Form 8-K | SEC EDGAR | +0.45% | +0.91% | |
| Summit Materials Announces Second Quarter 2024 Results Conference Call Date | Press release | PR Newswire | -0.65% | -1.38% | |
| Form 8-K Summit Materials, Inc. For: May 21 | SEC filing · Form 8-K | SEC EDGAR | -0.25% | -1.60% | |
| Form DEFA14A Summit Materials, Inc. | SEC filing · Form DEFA14A | SEC EDGAR | -0.75% | +0.95% | |
| Form 8-K Summit Materials, Inc. For: May 01 | SEC filing · Form 8-K | SEC EDGAR | +1.14% | +2.76% | |
| Summit Materials, Inc. Reports First Quarter 2024 Results | Press release | PR Newswire | +1.14% | +2.76% | |
| Form 8-K Summit Materials, Inc. For: Apr 26 | SEC filing · Form 8-K | SEC EDGAR | -0.55% | +0.15% | |
| Summit Materials Announces First Quarter 2024 Results Conference Call Date | Press release | PR Newswire | +0.47% | -0.49% | |
| Form ARS Summit Materials, Inc. For: Dec 30 | SEC filing · Form ARS | SEC EDGAR | -0.20% | -1.27% | |
| Form DEF 14A Summit Materials, Inc. For: May 21 | SEC filing · Form DEF | SEC EDGAR | -0.20% | -1.27% | |
| Form DEFA14A Summit Materials, Inc. | SEC filing · Form DEFA14A | SEC EDGAR | -0.20% | -1.27% | |
| Form 8-K Summit Materials, Inc. For: Mar 13 | SEC filing · Form 8-K | SEC EDGAR | +0.52% | -0.14% | |
| Summit Materials, Inc. Provides Update on Its Elevate Strategy | Press release | PR Newswire | +0.52% | -0.14% | |
| Summit Materials to Host Investor Day on March 13, 2024 | Press release | PR Newswire | +0.07% | +3.82% | |
| Form 8-K Summit Materials, Inc. For: Feb 14 | SEC filing · Form 8-K | SEC EDGAR | -2.73% | -1.13% |
Each reaction is the move the market actually made, measured from the news timestamp. Headlines link through to the SUM section they belong to.
Where else SUM is measured.
SUM earnings → · Analyst actions → · SEC filings →
Other Basic Materials names, measured the same way
| Ticker | Events | Median 30-min | % positive |
|---|---|---|---|
| Masco Corporation (MAS) | 280 | +0.16% | 58% |
| SOUTH32 LTD SPNS/ADR (SOUHY) | 280 | 0.00% | 49% |
| Mosaic Company (The) (MOS) | 275 | +0.07% | 59% |
| Ur Energy Inc Common Shares (Canada) (URG) | 275 | -0.54% | 38% |
Same sector, same measurement: percent move vs. the price at the news timestamp, read at 30 minutes. Sample sizes differ, so the medians are comparable but the confidence behind them is not.
All Basic Materials names, measured the same way →
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Every name we’ve measured, in one place.
How the numbers are made.
How is Summit Materials, Inc. Class A's median reaction calculated?
Every labeled SUM news event is measured from its own timestamp: the last trade before the news is the base price, and the move is read at fixed horizons — 30 minutes of trading, then the close. The median across 276 events is what this page reports. Point-in-time, zero look-ahead: no event borrows information from a later one.
What counts as a positive reaction?
Any event whose price move is above zero at the horizon, relative to the last trade before the news timestamp. 44% of SUM's measured events are up at 30 minutes; the rest close the window flat or negative.
How often is this page updated?
The news table refreshes automatically as new events are labeled and priced. The reaction medians are re-pulled in batches from the dataset — the figures here are as of 2026-09-21.
Does SUM's past reaction predict its next one?
No. These are realized facts about past events, not forecasts. They describe a distribution — they say nothing certain about any future move.