Earnings Revision & Guidance Analysis
Overview
Track sell-side analyst estimate revisions, management guidance changes, and post-earnings price drift to generate investment signals. Earnings revisions are among the most persistent and well-documented alpha factors in equity markets — stocks with upward revisions tend to continue outperforming, and vice versa.
Core Concepts
1. Earnings Revision Momentum
The revision signal hierarchy (strongest to weakest):
| Signal Type | Description | Typical Alpha (annualized) | Persistence |
|---|---|---|---|
| Earnings surprise (beat/miss) | Actual EPS vs consensus | 3-8% post-event drift | 60-90 days (PEAD) |
| Consensus revision breadth | % of analysts revising up vs down | 4-6% long-short spread | 3-6 months |
| Estimate magnitude change | Size of revision relative to prior estimate | 3-5% | 1-3 months |
| Guidance revision | Management guidance change vs prior | 5-10% on event | Immediate + 30-60 day drift |
| Whisper number miss/beat | Actual vs buy-side whisper (not official consensus) | 2-4% | 1-2 weeks |
2. Key Metrics
Earnings Surprise:
python# Standardized Unexpected Earnings (SUE) sue = (actual_eps - consensus_eps) / std_of_forecast_errors # Interpretation # SUE > +2: large positive surprise → strong PEAD signal # SUE < -2: large negative surprise → strong negative PEAD # |SUE| < 0.5: in-line with expectations → weak signal
Revision Breadth:
python# Revision breadth ratio breadth = (num_upgrades - num_downgrades) / total_analysts # Interpretation # breadth > +0.5: strong consensus upgrade momentum # breadth < -0.5: strong consensus downgrade momentum # |breadth| < 0.2: mixed / no clear direction
Estimate Dispersion:
python# Analyst disagreement dispersion = std_of_estimates / abs(mean_estimate) # High dispersion (>15%): high uncertainty → larger potential surprise # Low dispersion (<5%): tight consensus → smaller surprise but higher confidence
3. Post-Earnings Announcement Drift (PEAD)
The most robust anomaly in equity markets: prices continue to drift in the direction of the earnings surprise for 60-90 days after the announcement.
PEAD trading rules:
| Surprise Quintile | Average 60-day Drift | Strategy |
|---|---|---|
| Q5 (top surprise) | +4 to +8% | Go long, hold 60-90 days |
| Q4 | +1 to +3% | Mild long |
| Q3 (in-line) | ~0% | No action |
| Q2 | -1 to -3% | Mild short / underweight |
| Q1 (worst surprise) | -4 to -8% | Go short / avoid, hold 60-90 days |
PEAD enhancement filters:
- Small/mid cap > large cap (less analyst coverage = slower price discovery)
- Low institutional ownership > high ownership (slower information diffusion)
- First surprise in a direction > consecutive same-direction surprises
- Revenue surprise + EPS surprise together > EPS surprise alone
4. Management Guidance Analysis
Guidance types:
| Type | What It Covers | Signal Weight |
|---|---|---|
| Revenue guidance | Top-line outlook | High (harder to manipulate) |
| EPS guidance | Bottom-line outlook | Medium (can be managed via buybacks, tax rate) |
| Margin guidance | Profitability trajectory | High (reflects pricing power and cost control) |
| CapEx guidance | Investment intentions | Medium (forward-looking growth signal) |
| Segment guidance | Division-level detail | High (reveals where growth is coming from) |
Guidance change signals:
python# Guidance revision scoring def score_guidance_change(current_guide, prior_guide, consensus): # Guide above consensus = positive signal if current_guide.midpoint > consensus * 1.02: guide_vs_consensus = "above" elif current_guide.midpoint < consensus * 0.98: guide_vs_consensus = "below" else: guide_vs_consensus = "inline" # Guide raised vs lowered vs maintained if prior_guide: if current_guide.midpoint > prior_guide.midpoint * 1.01: guide_revision = "raised" elif current_guide.midpoint < prior_guide.midpoint * 0.99: guide_revision = "lowered" else: guide_revision = "maintained" # Strongest signal: raised guidance above consensus # Weakest signal: lowered guidance below consensus
Guidance language analysis:
| Language Pattern | Interpretation | Signal |
|---|---|---|
| "Raising full-year outlook" | Confidence in acceleration | Strong positive |
| "Reaffirming guidance" | No change, on-track | Mild positive (met expectations) |
| "Narrowing guidance range to upper half" | Soft raise without formal revision | Positive |
| "Updating guidance to reflect..." | Euphemism for guidance cut | Negative |
| "Withdrawing guidance" | High uncertainty, loss of visibility | Strong negative |
| "Providing preliminary results" | Pre-announcement, usually bad news | Negative (if below consensus) |
5. Earnings Quality Indicators
Red flags in earnings reports:
- Revenue growing but cash flow declining → accrual manipulation
- Changing revenue recognition policy → inflating top line
- Declining DSO (Days Sales Outstanding) story contradicted by rising AR → channel stuffing
- Beating EPS via lower tax rate or share buyback, not operating improvement
- Frequent "non-GAAP adjustments" that always add back expenses → questionable earnings quality
- Inventory build outpacing revenue growth → future write-down risk
Quality scoring:
pythonearnings_quality = { "fcf_conversion": fcf / net_income, # >0.8 = good, <0.5 = poor "accrual_ratio": (net_income - ocf) / avg_assets, # <5% = good, >10% = concern "revenue_cash_alignment": revenue_growth - ocf_growth, # small gap = good "non_gaap_gap": non_gaap_eps - gaap_eps, # large gap = red flag "buyback_eps_boost": eps_growth - net_income_growth, # large = artificial }
Earnings Calendar and Workflow
Pre-Earnings Analysis Checklist
- Consensus snapshot: current EPS/revenue consensus, revision trend (30d/60d/90d)
- Historical surprise pattern: has the company consistently beat/missed? By how much?
- Guidance comparison: last quarter's guidance vs current consensus
- Whisper number: buy-side expectations (often 1-3% above street consensus for serial beaters)
- Options market pricing: implied move from at-the-money straddle
- Sector peers already reported: read-through signals from competitors
Post-Earnings Analysis Checklist
- Headline numbers: EPS surprise %, revenue surprise %
- Quality of beat/miss: operating income-driven or one-time items?
- Guidance change: raised / maintained / lowered / withdrawn
- Call tone: management confidence level, Q&A defensiveness
- Analyst reaction: immediate revision direction (first 24-48 hours)
- Price/volume reaction: gap up/down, reversal, volume multiple vs average
Multi-Market Considerations
US Equities
- Earnings season: Jan/Apr/Jul/Oct (roughly 2-6 weeks after quarter-end)
- Data: SEC filings (10-Q within 40 days, 10-K within 60 days for large accelerated filers)
- Consensus: Bloomberg, Refinitiv, FactSet, Visible Alpha
- Via yfinance:
ticker.earnings_dates,ticker.earnings_history
Hong Kong Equities
- Earnings season: Mar-Apr (annual), Aug-Sep (interim)
- Many HK-listed companies report semi-annually, not quarterly
- Dual-listed (A+H): compare A-share analyst estimates vs HK analyst estimates for arbitrage
- Via yfinance:
yf.Ticker("0700.HK").financials
Key Differences
| Dimension | US | HK |
|---|---|---|
| Reporting frequency | Quarterly | Semi-annual (most) |
| Guidance practice | Common | Rare |
| Analyst coverage | Deep (>20 for large caps) | Thinner (5-15 for large caps) |
| Pre-announcement | Regulated (Reg FD) | Less regulated |
| Earnings call | Standard | Less common for mid/small caps |
Output Format
## Earnings Revision Analysis — [Ticker] ### Consensus Snapshot - **Current FY EPS consensus**: $X.XX (N analysts) - **30-day revision**: [up/down X%] — [N upgrades / N downgrades] - **60-day revision**: [up/down X%] - **Estimate dispersion**: [low/medium/high] (CV = X%) ### Last Earnings Event - **Date**: YYYY-MM-DD | **Quarter**: FY25Q3 - **EPS**: $X.XX actual vs $X.XX consensus (surprise: +X%) - **Revenue**: $X.XB actual vs $X.XB consensus (surprise: +X%) - **Guidance**: [raised / maintained / lowered] — FY25 EPS guide: $X.XX-$X.XX - **Price reaction**: [+X% on day, +X% over 5 days] ### Revision Momentum - **Breadth**: [+0.6 → strong upgrade momentum] - **Magnitude**: [average revision +X% over 30 days] - **PEAD status**: [still within 60-day drift window / drift exhausted] ### Earnings Quality - **FCF conversion**: X% [strong/adequate/weak] - **Accrual ratio**: X% [clean/moderate/concern] - **Non-GAAP gap**: $X.XX [small/large] ### Signal - **Direction**: [bullish / neutral / bearish] - **Catalyst**: [next earnings date: YYYY-MM-DD] - **Confidence**: [high / medium / low]
Notes
- Earnings revision data requires real-time consensus feeds (Bloomberg, Refinitiv) for professional-grade signals; yfinance provides historical actuals but not real-time consensus
- PEAD is strongest in the first 30 days post-announcement; signal decays significantly after 60 days
- Guidance withdrawals are almost always negative — companies rarely withdraw guidance when business is going well
- Beware of "beat and lower" — beating current quarter but lowering forward guidance is often net negative
- This framework is for research purposes only and does not constitute investment advice
