1,488
ISINs Screened
60
Serial Acquirers
308+
M&A Transactions
p=0.015p-value of 0.015 - there is only a 1.5% chance of seeing this result by random luck. Below 5% is the standard bar for "statistically significant."
DiD Significance

5-Day CAAR by HIP ESG Tier

High ESG (0.536 avg)
20 firms, 83 deals • Market reward for ESG-aligned acquirers
+1.33%
CAAR
Medium ESG (0.373 avg)
20 firms, 139 deals • Near-neutral market reaction
+0.33%
CAAR
Low ESG (0.163 avg)
20 firms, 86 deals • Negative announcement reaction
-0.81%
CAAR
HIGH
+1.33%
MED
+0.33%
LOW
-0.81%

5-day cumulative average abnormal return (CAAR), event window [-2,+2]

Panel Fixed-Effects Results

Term Coeff. p-value
Intercept (b₀b₀ (b-zero) is the baseline level when every other variable is set to zero - the average return for low-ESG firms before the deal.) -0.812 0.031*
Post (b₁b₁ measures how much the outcome shifts after the event for the comparison group - the post-deal change for low-ESG acquirers.) +0.341 0.214
Treated (b₂b₂ measures the pre-existing difference between treated and control groups - how much high-ESG firms already differed before the deal.) +0.892 0.088
Post x Treated (b₃b₃ (b-three) is the difference-in-differences interaction coefficient: the extra change for the treated group (high-ESG firms) caused by the event, beyond what the control group experienced. This is the headline causal estimate.) +1.700**Two asterisks: significant at the 5% level (p < 0.05). The conventional bar for "statistically significant." 0.015

R² = 0.207R-squared = 0.207 means the model explains 20.7% of the variation in returns across firms. For cross-sectional finance research, that is a meaningful share.  |  N = 360 obs  |  Industry + Year FE

Test Stat Result
Kruskal-WallisKruskal-Wallis test: a non-parametric way to check whether three or more groups have different distributions. Works even when the data is not normally distributed. H=36.18** p < 0.001p-value below 0.1% - probability of this happening by chance is less than 1 in 1,000. Extremely strong evidence the effect is real.
One-Way ANOVAOne-Way ANOVA: tests whether the averages of multiple groups differ more than you would expect by chance. F=38.66** p < 0.001
Placebo (N=1,000) 0 / 1,000 No replication
Industrials Technology Financials Consumer Disc. Materials Energy Healthcare

7 sectors confirmed; no significant sector-level moderation of ESG-return relationship (H7 null, p=0.34p-value of 0.34 - a 34% chance of seeing this by luck alone. Above 5% means there is no reliable effect; the result is "null.").

Supp.
H1: HIGH tier generates positive CAAR (+1.33%)
Supp.
H2: LOW tier generates negative CAAR (-0.81%)
Supp.
H3: Significant HIGH/LOW gap (2.14 pp, p=0.015)
Supp.
H4: DiD b₃ positive and significant (+1.700**)
Supp.
H5: Non-parametric tests confirm (KW, ANOVAANOVA (Analysis of Variance): tests whether group means differ more than would be expected by chance.)
Supp.
H6: Placebo validates causal interpretation
Null
H7: No sector moderation (F=1.12, p=0.34)
Null
H8: No temporal trend in ESG-return relationship
Sample Size
1,488
ISINs screened from A-share universe; 60 serial acquirers retained
Transactions
308+
M&A deals from CSMAR / Wind; 3+ per acquirer threshold
Panel Obs.
360
Usable observations after HIP score availability filter
Placebo Test
0 / 1,000
Random tier assignments that replicate b₃ = +1.700b₃ = +1.700: the difference-in-differences interaction coefficient. High-ESG firms gained an extra 1.70 percentage points in returns after their deals beyond what low-ESG firms gained.
Key Implication
HIP ESG scores function as a statistically significant, economically meaningful signal for predicting post-acquisition market performance among Chinese serial acquirers. ESG integration should be treated as a material screening criterion in Chinese M&A evaluation frameworks.