Sen. Susan M. Collins

Question
Is trading concentrated in a few companies rather than spread across a diversified portfolio?

Insider signature
Informed trading concentrates in the few issuers tied to the information.

Analyst note
Dollar HHI 0.851 (identified set [0.591, 0.948]); trade-count HHI 0.007 vs. 95th percentile 0.006 of 345 random draws from all congressional trades (p = 0.004). Normalized sector entropy 0.12 [0.05, 0.90]. Top three issuers (MMM, RHT, SYK) carry at least 78% of dollar volume.

Evidence

Statistical

Effective number of issuers

1 [1, 2] 90%

Question
Were trades disclosed within the STOCK Act's 45-day limit?

Insider signature
Delayed disclosure can conceal well-timed trades.

Analyst note
Late share 0.007, Wilson [0.003, 0.019]; 90th percentile lag 35 days; longest 440 days.

Evidence

Descriptive

Late share

0.8% [0.3%, 1.9%] 90%

Question
Did trades in stocks affected by the member's legislative work come before votes and move the right way?

Insider signature
Trading on knowledge of legislation before it is public.

Analyst note
theta_9 = 0.0002; pre-event minus other trades = 0.0101 [-0.0049, 0.0280], p = 0.158; mean pre-trade drift psi = 0.0036.

Evidence

Statistical

Pre-event minus other trades, signed CAR

+1.01% [−0.49%, +2.80%] 90%

p-value

0.158

Holm-adjusted p

1.000

BH q-value

0.707

Margin δ

0.5% per trade

Robust to variants

No, reading changes under some variants

Question
When a traded stock made a large unexpected move soon after the trade, was the trade on the right side?

Insider signature
Buying shortly before a large jump or selling shortly before a large drop.

Analyst note
Hit rate 0.62, Clopper-Pearson [0.39, 0.82], exact one-sided p = 0.227; threshold |AR| > 3 sigma.

Evidence

Statistical

Hit rate

62.5% [39.1%, 82.2%] 90%

p-value

0.227

Holm-adjusted p

1.000

BH q-value

1.000

Margin δ

10 points above a coin flip

Question
Are the member's trades unusually large, especially just before news?

Insider signature
Informed trades are large relative to the trader's normal activity, because the profit from an informational edge scales with position size.

Analyst note
Lowest-band share 0.812, 90% Wilson [0.775, 0.844]. Event-linked size gap Delta_z = 0.00 (within-issuer permutation p = 1.000); 0 event-linked trades with z > 3 in bands of $50,001 or more.

Evidence

Statistical

Lowest-band share

81.2% [77.5%, 84.4%] 90%

p-value

1.000

Holm-adjusted p

1.000

BH q-value

1.000

Question
Do trades arrive in routine rebalancing batches, or sporadically just before company news?

Insider signature
Opportunistic trades carry information and routine trades do not.

Analyst note
Batch-day share 23/81, Wilson [0.21, 0.37]; index of dispersion 22.96 (chi-square p = 0); routine share 0.01 (portfolio-routine or Cohen-Malloy-Pomorski two-year rule). Proximity share 0.020 vs. circular-shift null mean 0.040, p = 0.896.

Evidence

Statistical

Batch-day share

28.4% [21.0%, 37.2%] 90%

p-value

0.896

Holm-adjusted p

1.000

BH q-value

1.000

Question
Do purchases rise and sales fall more than the market in the weeks after the trade?

Insider signature
Purchases before price rises and sales before price falls.

Analyst note
Mean signed CAR(1,21) = -0.0084; 90% KP interval [-0.0206, 0.0037]; t_BMP = -1.85, r-bar = 0.014, t_KP = -1.08, Patell Z = -2.05, Corrado Z = -1.99. Dollar-weighted identified set [-0.0205, -0.0164]. Calendar-time alpha -21.21%/yr (NW t = -2.61, 584 days).

Evidence

Statistical

Mean signed 21-day CAR

−0.84% [−2.06%, +0.37%] 90%

p-value

0.995

Holm-adjusted p

1.000

BH q-value

0.995

Margin δ

0.5% per trade over 21 days

Robust to variants

No, reading changes under some variants

Question
Does the member trade industries their committees oversee, and do those trades do better?

Insider signature
Members may trade on information about industries their committees oversee.

Analyst note
Committees SLIN, SSAP, SSHR; jurisdiction sectors Aerospace & Defense, Health Care, Human Resource & Employment Services, Systems Software. Dollar share 0.010 (identified set [0.003, 0.036], bootstrap 0.002-0.192); benchmarks S&P 500 0.162, congressional peers 0.177.

Evidence

Descriptive

Jurisdiction excess share

-16.7% [-17.6%, 1.5%] 90%

Margin δ

0.5% per trade over 21 days

Question
After accounting for noise, does the member's trading beat that of other members?

Insider signature
A member with an information edge stands out from the cross-section of congressional traders.

Analyst note
Empirical Bayes: raw -0.0084, posterior -0.0028 (sd 0.0015); Congress mean -0.0028, between-member variance 0.000000.

Evidence

Statistical

Shrunk signed 21-day CAR

−0.28% [−0.53%, −0.03%] 90%

Margin δ

0.5% per trade over 21 days

Question
Does the member trade the same stock in the same direction as other members at the same time more than chance predicts?

Insider signature
Shared nonpublic information spreads through networks and shows up as clustered trades.

Analyst note
Co-traded share 0.061; circular-shift null mean 0.077, 95th pct 0.108, p = 0.840. Co-traded signed CAR 0.0109, p = 0.287.

Evidence

Statistical

Co-traded share

6.1%

p-value

0.287

Holm-adjusted p

1.000

BH q-value

0.902

Robust to variants

Yes

Question
Do trades in a spouse's or dependent's name do better than the member's own?

Insider signature
Routing informed trades through family accounts.

Analyst note
Family signed CAR -0.0080 [-0.0195, 0.0036], t_KP = -1.11.

Evidence

Statistical

Family-account signed CAR

−0.80% [−1.95%, +0.36%] 90%

p-value

0.865

Holm-adjusted p

1.000

BH q-value

0.948

Margin δ

0.5% per trade over 21 days

Question
Does the member use options, and do option trades point the right way?

Insider signature
Informed traders favour options because leverage raises the payoff to private information.

Analyst note
No option trades were reported.

Evidence

Descriptive

Margin δ

0.5% per trade over 21 days

Question
Before the market's biggest moves, did the member's trades point the right way?

Insider signature
An informed trader's trades just before a market-moving event point in the direction of the coming move.

Analyst note
Hit rate 0.57, Clopper-Pearson 90% [0.23, 0.87]; exact one-sided p = 0.500; magnitude-weighted sign-flip p = 0.441. Episodes: benchmark days beyond three rolling standard deviations with trades in the prior five trading days, plus documented episodes when supplied.

Evidence

Statistical

Hit rate

57.1% [22.5%, 87.1%] 90%

p-value

0.500

Holm-adjusted p

1.000

BH q-value

1.000

Margin δ

10 points above a coin flip

Question
Does the member direct the trades, and does trading change when the member's access to information changes?

Insider signature
The person holding the information directs the trade.

Analyst note
No documentary record of trading arrangements or absence periods was available.

Evidence

Not computed

Question
Did trading change after press scrutiny or an ethics inquiry?

Insider signature
A member who trades on information has an incentive to keep control of trading after scrutiny.

Analyst note
No documented scrutiny date; the estimated change point in trading activity is shown for reference. Estimated change point 2014-04-24 (permutation p = 0.002).

Evidence

Descriptive

Question
Does the member buy and sell the same stock within six months, and do those round trips beat the market?

Insider signature
Short-horizon round trips capture a temporary informational edge.

Analyst note
Opening-trade signed CAR(1,21) -0.0338 [-0.0972, 0.0296], t_KP = -1.36, over 5 priced openings. Realized market-adjusted return to the closing trade averaged -2.00% (win rate 50%); it is shown for context only because exit timing is chosen after the fact.

Evidence

Statistical

Opening-trade signed 21-day CAR

−3.38% [−9.72%, +2.96%] 90%

p-value

0.877

Holm-adjusted p

1.000

BH q-value

0.999

Margin δ

0.5% per trade over 21 days