Amphastar Pharmaceuticals, Inc. (AMPH)
AMPH moved a median of +0.07% 30 minutes after news, and -0.49% by the close. How AMPH actually reacts to news — the realized, point-in-time move the market made, measured across 294 labeled events over the last three years with zero look-ahead.
AMPH’s median reaction, across the day.
| Horizon | Median | % positive | Events |
|---|---|---|---|
| 5-min | +0.15% | 57% | 293 |
| 30-min | +0.07% | 52% | 293 |
| 60-min | 0.00% | 50% | 293 |
| to close | -0.49% | 41% | 290 |
| Middle 50% of AMPH reactions | -0.70% to +0.92% |
|---|---|
| Median reaction (30-min) | +0.07% |
| Measured reactions | 294 |
Half of all Amphastar Pharmaceuticals, Inc. news events land between -0.70% and +0.92% at 30 minutes.
Reaction stats as of 2026-08-31. Newest measured event . Reaction = percent move vs. the price at the news timestamp.
How AMPH reacts, by analyst action.
| Event | Events | Median 30-min | % positive | Median to close |
|---|---|---|---|---|
| Analyst upgrades | 14 | +0.58% | 57% | +0.03% |
| Analyst downgrades | 29 | +0.35% | 69% | +0.49% |
| Coverage initiations | 13 | -0.54% | 46% | -0.43% |
| Rating reiterations | 34 | -0.34% | 41% | -0.76% |
| Price-target cuts | 10 | +0.07% | 50% | -0.60% |
Last 3 years, pulled 2026-08-31. 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 AMPH ranks against every other measured name →
That’s how AMPH usually reacts — get an email when it moves on news →Email me when AMPH moves on news.
One email per qualifying move — the headline, the measured reaction, and how it compares to AMPH's baseline. Nothing else.
Recent AMPH events, each with its measured reaction.
| Date | Headline | Event | Source | 5-min | To close |
|---|---|---|---|---|---|
| Amphastar Pharmaceuticals to Present at the Wells Fargo 21st Annual Healthcare Conference | Press release | PR Newswire | +0.11% | +1.64% | |
| Amphastar Pharmaceuticals Reports Financial Results for the Three Months Ended June 30, 2026 | Press release | PR Newswire | -6.98% | -7.56% | |
| Form 10-Q Amphastar Pharmaceutical For: Jun 30 | SEC filing · Form 10-Q | SEC EDGAR | -6.98% | -7.56% | |
| Form 8-K Amphastar Pharmaceutical For: Aug 06 | SEC filing · Form 8-K | SEC EDGAR | -6.98% | -7.56% | |
| Amphastar Pharmaceuticals to Release Second Quarter Earnings and Hold Conference Call on August 6, 2026 | Press release | PR Newswire | +0.52% | +1.68% | |
| Form 8-K Amphastar Pharmaceutical For: Jul 09 | SEC filing · Form 8-K | SEC EDGAR | +0.00% | +1.53% | |
| Form 8-K Amphastar Pharmaceutical For: Jul 02 | SEC filing · Form 8-K | SEC EDGAR | -0.78% | -5.41% | |
| Form 8-K Amphastar Pharmaceutical For: Jun 01 | SEC filing · Form 8-K | SEC EDGAR | +1.15% | +2.30% | |
| Amphastar Pharmaceuticals to Present at the 2026 Jefferies Healthcare Conference | Press release | ACCESS Newswire | +1.44% | +2.03% | |
| Amphastar Pharmaceuticals Reports Financial Results for the Three Months Ended March 31, 2026 | Press release | ACCESS Newswire | -0.48% | +2.10% | |
| Form 10-Q Amphastar Pharmaceutical For: Mar 31 | SEC filing · Form 10-Q | SEC EDGAR | -0.48% | +2.10% | |
| Form 8-K Amphastar Pharmaceutical For: May 07 | SEC filing · Form 8-K | SEC EDGAR | -0.48% | +2.10% | |
| Amphastar Pharmaceuticals to Present at the 2026 Bank of America Health Care Conference | Press release | ACCESS Newswire | +1.02% | +1.70% | |
| Amphastar Pharmaceuticals to Release First Quarter Earnings and Hold Conference Call on May 7, 2026 | Press release | ACCESS Newswire | +0.32% | +1.53% | |
| Form ARS Amphastar Pharmaceutical For: Dec 31 | SEC filing · Form ARS | SEC EDGAR | -0.14% | +0.09% | |
| Form DEF 14A Amphastar Pharmaceutical For: Jun 01 | SEC filing · Form DEF | SEC EDGAR | -0.14% | +0.09% | |
| Form DEFA14A Amphastar Pharmaceutical | SEC filing · Form DEFA14A | SEC EDGAR | -0.14% | +0.09% | |
| Amphastar Pharmaceuticals to Present at the 25th Annual Needham Healthcare Conference | Press release | ACCESS Newswire | -0.47% | +0.64% | |
| Form 8-K Amphastar Pharmaceutical For: Mar 12 | SEC filing · Form 8-K | SEC EDGAR | +1.27% | +2.54% | |
| Form 8-K Amphastar Pharmaceutical For: Mar 03 | SEC filing · Form 8-K | SEC EDGAR | +0.16% | +1.26% | |
| Amphastar Pharmaceuticals Reports Financial Results for the Three Months and Full Year Ended December 31, 2025 | Press release | ACCESS Newswire | -1.60% | -9.85% | |
| Form 10-K Amphastar Pharmaceutical For: Dec 31 | SEC filing · Form 10-K | SEC EDGAR | -1.60% | -9.85% | |
| Form 8-K Amphastar Pharmaceutical For: Feb 26 | SEC filing · Form 8-K | SEC EDGAR | -1.60% | -9.85% | |
| Amphastar Announces FDA Approval for Ipratropium Bromide HFA | Press release | ACCESS Newswire | +0.04% | +0.07% | |
| Amphastar Pharmaceuticals to Release Fourth Quarter Earnings and Hold Conference Call on February 26, 2026 | Press release | ACCESS Newswire | -0.39% | -0.17% | |
| Amphastar Pharmaceuticals Announces Exclusive License Agreement with Nanjing Hanxin Pharmaceutical Technology Co., Ltd. for Fully Synthetic Corticotropin Compound | Press release | ACCESS Newswire | -0.17% | +4.81% | |
| Form 8-K Amphastar Pharmaceutical For: Jan 06 | SEC filing · Form 8-K | SEC EDGAR | -0.84% | -0.86% | |
| Amphastar Pharmaceuticals to Present at the J.P. Morgan 2026 Healthcare Conference | Press release | ACCESS Newswire | +0.86% | -1.80% | |
| Amphastar Announces FDA Approval for Teriparatide Injection | Press release | ACCESS Newswire | +0.39% | +2.06% | |
| Amphastar Pharmaceuticals to Present at the 37th Annual Piper Sandler Healthcare Conference | Press release | ACCESS Newswire | +0.85% | +2.89% | |
| Amphastar Pharmaceuticals to Present at the Jefferies Global Healthcare Conference | Press release | ACCESS Newswire | +1.03% | +2.47% | |
| Amphastar Pharmaceuticals Reports Financial Results for the Three Months Ended September 30, 2025 | Press release | ACCESS Newswire | -4.89% | -8.11% | |
| Form 10-Q Amphastar Pharmaceutical For: Sep 30 | SEC filing · Form 10-Q | SEC EDGAR | -4.89% | -8.11% | |
| Form 8-K Amphastar Pharmaceutical For: Nov 06 | SEC filing · Form 8-K | SEC EDGAR | -4.89% | -8.11% | |
| Amphastar Pharmaceuticals to Release Third Quarter Earnings and Hold Conference Call on November 6th, 2025 | Press release | ACCESS Newswire | +0.31% | -1.40% | |
| Form 8-K Amphastar Pharmaceutical For: Oct 21 | SEC filing · Form 8-K | SEC EDGAR | +0.31% | -1.40% | |
| Form 8-K Amphastar Pharmaceutical For: Sep 15 | SEC filing · Form 8-K | SEC EDGAR | -0.91% | +0.99% | |
| Amphastar Pharmaceuticals to Present at the 2025 Wells Fargo Healthcare Conference | Press release | ACCESS Newswire | -0.36% | -0.79% | |
| Amphastar Pharmaceuticals Bolsters Proprietary Pipeline Through Exclusive Licensing Agreement with Nanjing Anji Biotechnology Co., Ltd. | Press release | ACCESS Newswire | +0.29% | — | |
| Form 8-K Amphastar Pharmaceutical For: Aug 08 | SEC filing · Form 8-K | SEC EDGAR | +0.40% | — | |
| Amphastar Announces FDA Approval for Iron Sucrose Injection, USP | Press release | ACCESS Newswire | +7.07% | +10.54% | |
| Amphastar Pharmaceuticals Reports Financial Results for the Three Months Ended June 30, 2025 | Press release | ACCESS Newswire | +4.67% | +7.88% | |
| Form 10-Q Amphastar Pharmaceutical For: Jun 30 | SEC filing · Form 10-Q | SEC EDGAR | +4.67% | +7.88% | |
| Form 8-K Amphastar Pharmaceutical For: Aug 07 | SEC filing · Form 8-K | SEC EDGAR | +4.67% | +7.88% | |
| Amphastar Pharmaceuticals to Release Second Quarter Earnings and Hold Conference Call on August 7th, 2025 | Press release | ACCESS Newswire | -2.04% | — | |
| Form 8-K Amphastar Pharmaceutical For: Jul 18 | SEC filing · Form 8-K | SEC EDGAR | +1.55% | +0.28% | |
| Amphastar Pharmaceuticals Aims to Quadruple Domestic Manufacturing Capacity at Rancho Cucamonga Headquarters | Press release | ACCESS Newswire | +0.20% | -4.21% | |
| Form 8-K Amphastar Pharmaceutical For: Jun 02 | SEC filing · Form 8-K | SEC EDGAR | +0.90% | -0.58% | |
| Amphastar Pharmaceuticals to Present at the Jefferies Global Healthcare Conference | Press release | ACCESS Newswire | +0.92% | +1.09% | |
| Amphastar Pharmaceuticals to Present at the 2025 Bank of America Health Care Conference | Press release | ACCESS Newswire | +0.67% | -1.75% |
Each reaction is the move the market actually made, measured from the news timestamp. Headlines link through to the AMPH section they belong to.
Where else AMPH is measured.
AMPH earnings → · Analyst actions → · SEC filings →
Other Healthcare names, measured the same way
| Ticker | Events | Median 30-min | % positive |
|---|---|---|---|
| GeoVax Labs, Inc. (GOVX) | 296 | -0.65% | 34% |
| Repligen Corporation (RGEN) | 295 | +0.15% | 55% |
| IPSEN SA S/ADR (IPSEY) | 293 | 0.00% | 6% |
| Trinity Biotech plc - American Depositary Shares (TRIB) | 293 | -0.13% | 42% |
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 Healthcare names, measured the same way →
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How the numbers are made.
How is Amphastar Pharmaceuticals, Inc.'s median reaction calculated?
Every labeled AMPH 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 294 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. 52% of AMPH'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 2026-08-31.
Does AMPH'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.