Koppers Holdings Inc. Koppers Holdings Inc. (KOP)
KOP moved a median of -0.21% 30 minutes after news, and +0.13% by the close. How KOP actually reacts to news — the realized, point-in-time move the market made, measured across 433 labeled events over the last three years with zero look-ahead.
KOP’s median reaction, across the day.
| Horizon | Median | % positive | Events |
|---|---|---|---|
| 5-min | 0.00% | 34% | 419 |
| 30-min | -0.21% | 44% | 433 |
| 60-min | -0.09% | 47% | 433 |
| to close | +0.13% | 51% | 429 |
| Middle 50% of KOP reactions | -0.85% to +0.54% |
|---|---|
| Median reaction (30-min) | -0.21% |
| Measured reactions | 433 |
Half of all Koppers Holdings Inc. Koppers Holdings Inc. news events land between -0.85% and +0.54% at 30 minutes.
Reaction stats as of 2026-09-21. Newest measured event . Reaction = percent move vs. the price at the news timestamp.
How KOP reacts, by analyst action.
| Event | Events | Median 30-min | % positive | Median to close |
|---|---|---|---|---|
| Analyst upgrades | 12 | +0.39% | 67% | +0.97% |
| Rating reiterations | 37 | -0.14% | 41% | +0.57% |
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. 2 further classes were observed with fewer than 10 measured events and are not published. See how KOP ranks against every other measured name →
That’s how KOP usually reacts — get an email when it moves on news →Email me when KOP moves on news.
One email per qualifying move — the headline, the measured reaction, and how it compares to KOP's baseline. Nothing else.
Recent KOP events, each with its measured reaction.
| Date | Headline | Event | Source | 5-min | To close |
|---|---|---|---|---|---|
| Koppers Holdings Inc. to Host Investor Day on September 17, 2026 | Press release | PR Newswire | -0.23% | -2.61% | |
| Koppers Management Meeting with Financial Community in Montreal and Toronto | Press release | PR Newswire | -1.22% | — | |
| Form 10-Q Koppers Holdings Inc. For: Jun 30 | SEC filing · Form 10-Q | SEC EDGAR | +0.10% | +3.07% | |
| Form 8-K Koppers Holdings Inc. For: Aug 06 | SEC filing · Form 8-K | SEC EDGAR | +1.44% | +7.61% | |
| KOPPERS REPORTS SECOND QUARTER 2026 RESULTS | Press release | PR Newswire | +1.44% | +7.61% | |
| Koppers Holdings Inc. Declares Quarterly Cash Dividend | Press release | PR Newswire | +0.05% | -1.30% | |
| Koppers Holdings Inc. Schedules Second Quarter 2026 Conference Call | Press release | PR Newswire | -0.06% | -2.08% | |
| Koppers Publishes 2025 Corporate Sustainability Report Highlighting Record Safety and Emissions Performance and Refreshed 2030 Strategy | Press release | PR Newswire | -0.51% | +0.56% | |
| Koppers Announces Participation in Upcoming June Investor Conferences | Press release | PR Newswire | -0.20% | +0.75% | |
| Koppers Management Participating in Wells Fargo Industrials & Materials Conference | Press release | PR Newswire | -1.46% | +0.00% | |
| Koppers Management Participating in Barrington Research Spring Investment Conference | Press release | PR Newswire | +0.00% | +0.77% | |
| Koppers Management Participating in Barclays Leveraged Finance Conference | Press release | PR Newswire | +0.00% | -3.67% | |
| Form 8-K Koppers Holdings Inc. For: May 11 | SEC filing · Form 8-K | SEC EDGAR | -0.36% | -2.09% | |
| Koppers Announces Appointment of Eric Brenner as Chief Financial Officer and Treasurer | Press release | PR Newswire | -0.36% | -2.09% | |
| Form 10-Q Koppers Holdings Inc. For: Mar 31 | SEC filing · Form 10-Q | SEC EDGAR | -0.55% | -3.81% | |
| Form 8-K Koppers Holdings Inc. For: May 07 | SEC filing · Form 8-K | SEC EDGAR | -1.94% | -0.88% | |
| Form S-8 Koppers Holdings Inc. | SEC filing · Form S-8 | SEC EDGAR | -1.94% | -0.88% | |
| Koppers Announces Conditional Plan to Discontinue Production Activities at Facility in Stickney, Illinois | Press release | PR Newswire | -1.94% | -0.88% | |
| KOPPERS REPORTS FIRST QUARTER 2026 RESULTS | Press release | PR Newswire | -1.94% | -0.88% | |
| Form 8-K/A Koppers Holdings Inc. For: Nov 05 | SEC filing · Form 8-K | SEC EDGAR | -1.94% | -0.88% | |
| Koppers Holdings Inc. Declares Quarterly Cash Dividend | Press release | PR Newswire | +0.36% | -0.48% | |
| Koppers Holdings Inc. Schedules First Quarter 2026 Conference Call | Press release | PR Newswire | -0.33% | +3.28% | |
| Koppers Holdings Publishes 2025 Annual Report | Press release | PR Newswire | -0.61% | +0.18% | |
| Koppers to Ring NYSE Closing Bell to Celebrate 20th Anniversary of Listing; Management Hosting Meetings with the Financial Community in New York | Press release | PR Newswire | -0.81% | -0.60% | |
| Form ARS Koppers Holdings Inc. For: Dec 31 | SEC filing · Form ARS | SEC EDGAR | -0.81% | -0.60% | |
| Form DEF 14A Koppers Holdings Inc. For: May 07 | SEC filing · Form DEF | SEC EDGAR | -0.81% | -0.60% | |
| Form 8-K/A Koppers Holdings Inc. For: Jan 05 | SEC filing · Form 8-K | SEC EDGAR | +0.72% | +1.44% | |
| Koppers Management Participating in Sidoti Small Cap Conference | Press release | PR Newswire | +0.59% | +1.24% | |
| Koppers Management Participating in NYSE Materials Virtual Investor Access Day | Press release | PR Newswire | -0.81% | +4.58% | |
| Form 10-K Koppers Holdings Inc. For: Dec 31 | SEC filing · Form 10-K | SEC EDGAR | — | +5.29% | |
| Form 8-K Koppers Holdings Inc. For: Feb 26 | SEC filing · Form 8-K | SEC EDGAR | +2.54% | +4.90% | |
| KOPPERS REPORTS FOURTH QUARTER AND FULL-YEAR 2025 RESULTS; PROVIDES 2026 OUTLOOK | Press release | PR Newswire | +2.54% | +4.90% | |
| Koppers Holdings Inc. Announces Increase to Quarterly Cash Dividend | Press release | PR Newswire | +1.06% | +3.92% | |
| Koppers Holdings Inc. Schedules Fourth Quarter and Full-Year 2025 Conference Call | Press release | PR Newswire | -0.39% | +0.61% | |
| Form 8-K Koppers Holdings Inc. For: Jan 05 | SEC filing · Form 8-K | SEC EDGAR | +0.89% | +4.77% | |
| Koppers Announces Retirement of Chief Financial Officer Jimmi Sue Smith | Press release | PR Newswire | +0.89% | +4.77% | |
| Koppers Named To Newsweek 'America's Most Responsible Companies' Listing | Press release | PR Newswire | -1.23% | +0.53% | |
| Koppers Management Participating in Sidoti Year End Virtual Investor Conference | Press release | PR Newswire | +0.00% | -0.11% | |
| Form 8-K/A Koppers Holdings Inc. For: Nov 08 | SEC filing · Form 8-K | SEC EDGAR | -0.36% | -3.54% | |
| Koppers Management Participating in BofA Securities Leveraged Finance Conference | Press release | PR Newswire | -0.30% | +0.17% | |
| Koppers Announces Participation in Southwest IDEAS Investor Conference | Press release | PR Newswire | +0.00% | -3.87% | |
| Form 10-Q Koppers Holdings Inc. For: Sep 30 | SEC filing · Form 10-Q | SEC EDGAR | +0.25% | +1.64% | |
| Form 8-K Koppers Holdings Inc. For: Nov 07 | SEC filing · Form 8-K | SEC EDGAR | -0.80% | -6.81% | |
| KOPPERS REPORTS THIRD QUARTER 2025 RESULTS | Press release | PR Newswire | -0.80% | -6.81% | |
| Koppers Holdings Inc. Declares Quarterly Cash Dividend | Press release | PR Newswire | — | -1.10% | |
| Form 8-K Koppers Holdings Inc. For: Nov 05 | SEC filing · Form 8-K | SEC EDGAR | +0.00% | -1.10% | |
| Koppers Holdings Names Laura Posadas to Board | Press release | PR Newswire | +0.00% | -1.10% | |
| Koppers Holdings Inc. Schedules Third Quarter 2025 Conference Call | Press release | PR Newswire | +0.07% | +0.07% | |
| Koppers Management Meeting with Financial Community in Los Angeles | Press release | PR Newswire | +0.00% | -2.09% | |
| Koppers Announces Participation in Midwest IDEAS Investor Conference | Press release | PR Newswire | +0.56% | -0.21% |
Each reaction is the move the market actually made, measured from the news timestamp. Headlines link through to the KOP section they belong to.
Where else KOP is measured.
KOP earnings → · Analyst actions → · SEC filings →
Other Basic Materials names, measured the same way
| Ticker | Events | Median 30-min | % positive |
|---|---|---|---|
| Minerals Technologies Inc. (MTX) | 434 | -0.03% | 45% |
| Gevo, Inc. (GEVO) | 433 | +0.08% | 51% |
| Beacon Roofing Supply, Inc. (BECN) | 431 | +0.03% | 52% |
| HI-CRUSH PARTNERS (HCLP) | 431 | -0.06% | 43% |
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 Koppers Holdings Inc. Koppers Holdings Inc.'s median reaction calculated?
Every labeled KOP 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 433 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 KOP'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 KOP'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.