Ambac Financial Group, Inc. (AMBC)
AMBC moved a median of 0.00% 30 minutes after news, and -0.25% by the close. How AMBC actually reacts to news — the realized, point-in-time move the market made, measured across 312 labeled events over the last three years with zero look-ahead.
AMBC’s median reaction, across the day.
| Horizon | Median | % positive | Events |
|---|---|---|---|
| 5-min | +0.08% | 52% | 258 |
| 30-min | 0.00% | 52% | 258 |
| 60-min | -0.04% | 48% | 258 |
| to close | -0.25% | 41% | 257 |
| Middle 50% of AMBC reactions | -0.91% to +0.92% |
|---|---|
| Median reaction (30-min) | 0.00% |
| Measured reactions | 312 |
Half of all Ambac Financial Group, Inc. news events land between -0.91% and +0.92% at 30 minutes.
Reaction stats as of 2026-09-21. Newest measured event . Reaction = percent move vs. the price at the news timestamp.
Email me when AMBC moves on news.
One email per qualifying move — the headline, the measured reaction, and how it compares to AMBC's baseline. Nothing else.
Recent AMBC events, each with its measured reaction.
| Date | Headline | Event | Source | 5-min | To close |
|---|---|---|---|---|---|
| Form 10-Q OCTAVE SPECIALTY GROUP For: Jun 30 | SEC filing · Form 10-Q | SEC EDGAR | — | — | |
| Form 8-K OCTAVE SPECIALTY GROUP For: Aug 06 | SEC filing · Form 8-K | SEC EDGAR | — | — | |
| Form S-8 OCTAVE SPECIALTY GROUP | SEC filing · Form S-8 | SEC EDGAR | — | — | |
| Form S-8 POS OCTAVE SPECIALTY GROUP | SEC filing · Form S-8 | SEC EDGAR | — | — | |
| Form 8-K OCTAVE SPECIALTY GROUP For: May 28 | SEC filing · Form 8-K | SEC EDGAR | — | — | |
| Form DEFA14A OCTAVE SPECIALTY GROUP | SEC filing · Form DEFA14A | SEC EDGAR | — | — | |
| Form 10-Q OCTAVE SPECIALTY GROUP For: Mar 31 | SEC filing · Form 10-Q | SEC EDGAR | — | — | |
| Form 8-K OCTAVE SPECIALTY GROUP For: May 06 | SEC filing · Form 8-K | SEC EDGAR | — | — | |
| Form ARS OCTAVE SPECIALTY GROUP For: Dec 31 | SEC filing · Form ARS | SEC EDGAR | — | — | |
| Form DEF 14A OCTAVE SPECIALTY GROUP For: Dec 31 | SEC filing · Form DEF | SEC EDGAR | — | — | |
| Form DEFA14A OCTAVE SPECIALTY GROUP | SEC filing · Form DEFA14A | SEC EDGAR | — | — | |
| Form 8-K OCTAVE SPECIALTY GROUP For: Apr 01 | SEC filing · Form 8-K | SEC EDGAR | — | — | |
| Form 10-K OCTAVE SPECIALTY GROUP For: Dec 31 | SEC filing · Form 10-K | SEC EDGAR | — | — | |
| Form 8-K OCTAVE SPECIALTY GROUP For: Feb 23 | SEC filing · Form 8-K | SEC EDGAR | — | — | |
| Form 8-K OCTAVE SPECIALTY GROUP For: Jan 06 | SEC filing · Form 8-K | SEC EDGAR | — | — | |
| Form 8-K OCTAVE SPECIALTY GROUP For: Dec 10 | SEC filing · Form 8-K | SEC EDGAR | — | — | |
| Ambac Financial Group Appoints Karen Beyer Head of Investor Relations | Press release | Business Wire | +0.94% | +2.00% | |
| Ambac Financial Group Rebrands as Octave Specialty Group, Inc. | Press release | Business Wire | +0.34% | +12.63% | |
| Ambac Reports Third Quarter 2025 Results | Press release | Business Wire | +0.34% | +12.63% | |
| Form 10-Q AMBAC FINANCIAL GROUP For: Sep 30 | SEC filing · Form 10-Q | SEC EDGAR | +0.34% | +12.63% | |
| Form 8-K AMBAC FINANCIAL GROUP For: Nov 10 | SEC filing · Form 8-K | SEC EDGAR | +0.34% | +12.63% | |
| Ambac Financial Group Completes Acquisition of ArmadaCare | Press release | Business Wire | +0.36% | +2.79% | |
| Form 8-K AMBAC FINANCIAL GROUP For: Oct 31 | SEC filing · Form 8-K | SEC EDGAR | +0.80% | +3.54% | |
| Ambac to Release Third Quarter 2025 Results on November 10, 2025 | Press release | Business Wire | +0.81% | -1.63% | |
| Ambac Subsidiary Beat Capital Partners Launches 1889 Specialty Insurance Services, a Financial Institutions MGA Led by Blair Bartlett and Backed by A+ Rated Capacity | Press release | Business Wire | -0.06% | -1.96% | |
| Form 8-K AMBAC FINANCIAL GROUP For: Sep 30 | SEC filing · Form 8-K | SEC EDGAR | +0.60% | -1.69% | |
| Ambac Financial Group Completes Sale of Its Legacy Financial Guarantee Businesses to Oaktree | Press release | Business Wire | -10.82% | -9.74% | |
| Ambac Financial Group to Acquire Leading Supplemental Health Program Manager ArmadaCare | Press release | Business Wire | -10.82% | -9.74% | |
| Form 8-K AMBAC FINANCIAL GROUP For: Sep 29 | SEC filing · Form 8-K | SEC EDGAR | -10.82% | -9.74% | |
| E&S MGA Pivix Launches Casualty Program with Everspan | Press release | Business Wire | +0.91% | +3.17% | |
| Ambac Reports Second Quarter 2025 Results | Press release | Business Wire | +0.56% | -14.11% | |
| Form 10-Q AMBAC FINANCIAL GROUP For: Jun 30 | SEC filing · Form 10-Q | SEC EDGAR | +0.56% | -14.11% | |
| Form 8-K AMBAC FINANCIAL GROUP For: Aug 07 | SEC filing · Form 8-K | SEC EDGAR | +0.56% | -14.11% | |
| Ambac to Release Second Quarter 2025 Results on August 7, 2025 | Press release | Business Wire | -0.40% | -1.03% | |
| Ambac Reports That the Wisconsin Office of the Commissioner of Insurance Has Scheduled a Hearing on the Sale of Ambac's Legacy Business | Press release | Business Wire | +3.66% | +11.04% | |
| Ambac Financial Group and Oaktree announce an extension to the stock purchase agreement for the Financial Guarantee business | Press release | Business Wire | +4.03% | +5.00% | |
| Form 8-K AMBAC FINANCIAL GROUP For: Jul 03 | SEC filing · Form 8-K | SEC EDGAR | +4.03% | +5.00% | |
| Ambac Financial Group Provides Update on the Timing of the Sale of Its Legacy Financial Guarantee Business | Press release | Business Wire | -1.15% | -2.31% | |
| Form 8-K AMBAC FINANCIAL GROUP For: Jun 10 | SEC filing · Form 8-K | SEC EDGAR | -1.15% | -2.31% | |
| Form 8-K AMBAC FINANCIAL GROUP For: May 28 | SEC filing · Form 8-K | SEC EDGAR | +0.51% | +0.06% | |
| Aegis Energy Announces Partnership with Everspan Group for new Excess Program for Petroleum Gasoline Haulers | Press release | Business Wire | -0.06% | -3.09% | |
| Ambac Reports First Quarter 2025 Results | Press release | Business Wire | -9.07% | -13.21% | |
| Form 10-Q AMBAC FINANCIAL GROUP For: Mar 31 | SEC filing · Form 10-Q | SEC EDGAR | -9.07% | -13.21% | |
| Form 8-K AMBAC FINANCIAL GROUP For: May 12 | SEC filing · Form 8-K | SEC EDGAR | -9.07% | -13.21% | |
| Ambac to Release First Quarter 2025 Results on May 12, 2025 | Press release | Business Wire | +0.19% | +0.38% | |
| Form ARS AMBAC FINANCIAL GROUP For: Dec 31 | SEC filing · Form ARS | SEC EDGAR | +0.93% | +1.24% | |
| Form DEF 14A AMBAC FINANCIAL GROUP For: Dec 31 | SEC filing · Form DEF | SEC EDGAR | +0.93% | +1.24% | |
| Form DEFA14A AMBAC FINANCIAL GROUP | SEC filing · Form DEFA14A | SEC EDGAR | +0.93% | +1.24% | |
| Ambac Financial Group, Inc. Provides Update on the Sale of Its Legacy Financial Guarantee Business | Press release | Business Wire | -2.34% | -2.92% | |
| Ambac Announces Meeting and Record Date for 2025 Annual Meeting of Stockholders | Press release | Business Wire | +0.78% | +0.22% |
Each reaction is the move the market actually made, measured from the news timestamp. Headlines link through to the AMBC section they belong to.
Where else AMBC is measured.
AMBC earnings → · Analyst actions → · SEC filings →
Other Financial Services names, measured the same way
| Ticker | Events | Median 30-min | % positive |
|---|---|---|---|
| Old Republic International Corporation (ORI) | 315 | -0.03% | 47% |
| WSFS Financial Corporation (WSFS) | 315 | +0.05% | 54% |
| Civista Bancshares, Inc. (CIVB) | 312 | -0.07% | 45% |
| Community Trust Bancorp, Inc. (CTBI) | 312 | +0.06% | 55% |
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 Financial Services names, measured the same way →
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How the numbers are made.
How is Ambac Financial Group, Inc.'s median reaction calculated?
Every labeled AMBC 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 312 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 AMBC'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 AMBC'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.