10-K filing event-study empirical analysis

Corporate AI Communication and Capital Market Response

This dashboard asks whether AI-related language in firms' 10-K annual reports is associated with abnormal stock-market reactions around the 10-K filing date. It studies communication in public filings, not direct observation of actual AI adoption.

Scope: Fortune 2025 Top 100Event date: 10-K filing_dateWindows: [-1,+1], [0,+1], [0,+3], [0,+5]Estimation: [-250,-30]

1. Plain-Language Guide

For readers with no prior background

Research question

What is being tested?

When a firm talks more about AI in its annual report, does the market react differently around the day that report becomes public?

One-line finding

What did the evidence show?

10-K filings appear to attract investor attention, especially through abnormal trading volume, but AI-specific disclosure variation does not robustly explain short-window CAR in the current sample.

273
Observed 10-K Events
Annual-report filing events initially observed in the text dataset.
272
Usable Market Events
Events with sufficient stock-market data for event-study estimation.
21
Regression Rows
Coefficient rows in the regression summary output.
9
Placebo Rows
Pre-filing placebo coefficient rows in the diagnostics output.

2. Underlying Mechanism

Why AI language might matter

Public 10-K disclosure

AI-related language becomes observable to investors through a formal annual report.

Investor attention

Investors process whether the AI language signals innovation opportunity, risk exposure, or routine disclosure.

Trading response

Information processing can appear as abnormal trading volume even when prices do not move strongly.

Price adjustment

CAR changes only if the AI signal is value-relevant and separable from the other bundled 10-K information.

Mechanism implication: the strongest expected pattern is not necessarily price movement. Because 10-K reports contain many types of information, trading attention can be clearer than AI-specific CAR.

3. IV: Independent Variables

AI-related 10-K communication measures

VariablePlain meaningInterpretation boundary
AI_Related_Disclosure_IntensityHow intensively the 10-K report discusses AI.Keyword-based disclosure intensity; not direct actual AI adoption.
AI_RiskRelated_Topic_ShareHow much AI discussion appears in privacy, data, cybersecurity, legal, regulatory, or risk contexts.Topic-derived risk-context share; not a manual sentiment score.
AI_Risk_Orientation_ProxyWhether AI communication is framed more toward risk orientation than infrastructure opportunity.Proxy based on topic balance; not human-coded managerial intent.

4. DV: Dependent Variables

Market reaction outcomes

Price reaction

Cumulative Abnormal Return (CAR)

CAR asks whether the firm's stock return moved more than expected after accounting for normal market movement. It is the price-reaction outcome.

  • CAR_m1_p1: [-1,+1]
  • CAR_0_p1: [0,+1]
  • CAR_0_p3: [0,+3]
  • CAR_0_p5: [0,+5]
Attention / trading

Abnormal Volume

Abnormal volume asks whether trading activity increased unusually around the filing date. It is interpreted as investor attention and information processing.

  • AbnormalVolume_0_p1: [0,+1]
  • AbnormalVolume_0_p3: [0,+3]
  • AbnormalVolume_0_p5: [0,+5]

5. Model and Formula

How the test is implemented

Abnormal return and CAR

ARi,t = Ri,t − (αi + βiRm,t)
CARi,[a,b] = Σt=ab ARi,t

Meaning: subtract normal market-driven returns from the firm's actual return, then add the abnormal returns over the event window.

Regression model

Yi,t = β0 + β1AICommi,t + γXi,t + μi + λt + εi,t

Meaning: Y is CAR or abnormal volume. β1 tests whether AI-related 10-K communication is associated with the market reaction. μi controls for firm fixed effects and λt controls for year fixed effects.

6. Results

Descriptive and regression evidence

EvidenceCurrent outputPlain interpretation
Average CARCAR_m1_p1 0.0030; CAR_0_p1 0.0031; CAR_0_p3 0.0028; CAR_0_p5 0.0024Short-window average price reactions are small and slightly positive.
Average abnormal volumeAbnormalVolume_0_p1 0.6070; _0_p3 0.4614; _0_p5 0.3704Trading volume is visibly elevated, especially immediately after the filing.
Regression evidenceN=272; 21 coefficient rows; firm/year FE when feasible; firm-clustered SE or HC1 fallbackAI disclosure variables do not show a statistically significant short-window CAR association in the current sample.
Main conclusionAttention evidence stronger than AI-specific price evidence10-K filings attract market attention, but robust AI-specific CAR evidence is not established.

7. Placebo / Diagnostics

Checks before the event date

Placebo logic: if the same pattern appears before the filing, the event-window interpretation becomes weaker. The analysis uses pre-filing windows CAR_m10_m6, CAR_m5_m2, and AbnormalVolume_m5_m2. Current outputs contain 9 placebo coefficient rows, 10 model diagnostic rows, and merged_rows = 273.

8. Claim Boundaries

What this dashboard does not claim

Not actual AI adoption

The IVs are text-based disclosure proxies. They do not directly observe whether or how deeply a firm adopted AI.

Not standalone causality

The design provides event-window association evidence. It should not be read as standalone proof of an AI-specific causal effect.

Bundled 10-K information

10-K reports contain financial, risk, legal, and strategic information together. AI-specific effects are difficult to isolate.

9. Data Files

Generated repository outputs

FileStatus
data/derived/market_extension/daily_market_data_10k_events.csvGenerated; 73,746 rows
data/derived/market_extension/market_data_collection_report.csvGenerated; 273 rows
data/derived/market_extension/post_filing_market_reaction_estimates.csvGenerated; 273 rows, 272 estimated
data/derived/causal/ai_10k_event_study_analysis_dataset.csvGenerated; 273 rows
data/derived/causal/causal_event_study_regression_summary.csvGenerated; 21 coefficient rows
data/derived/causal/placebo_pre_filing_checks.csvGenerated; 9 placebo model rows