We are explicit about epistemic status: the filing-agency mechanism is an interpretation that organizes the results, not an identified causal estimate. The regimes differ in more than filing agency, and we did not observe who physically submitted each filing. The interpretation earns its place by parsimony — one institutional variable predicting the sign, the level gap, the transmission gap, and the individual-level distribution shape — and by surviving the alternatives considered next.

4.2 The measurement objection

Before external alternatives, one internal objection deserves direct treatment, because a careful reviewer will raise it first: is the contamination estimate partly mechanical? The post-window late rate is computed from filings made at the destination issuer, so if the destination's environment determines filing outcomes — which is the hypothesis — then some convergence of the insider's measured rate toward the destination's band mean is built into the design. A sharper variant asks whether the loop closes at the classification stage: the mover's own post-move filings enter the destination issuer's late rate, which defines the destination's band — do late-filing movers partly create the "High" label we then attribute their lateness to? Four responses.

First, the mechanical component is bounded by the same-culture baselines: a Medium→Medium mover experiences an equally mechanical change of measurement context, and their +7.1-point drift (Canada) is netted out of the cross-culture readings; what remains is variation attributable to the culture distance moved, not to moving per se.

Second, mechanical convergence to a destination mean cannot explain the shape of the individual-level distributions. Under pure convergence, Low→High movers in both regimes should cluster near the destination band's mean shortfall. Instead, Canadian movers deteriorate almost universally (97.3% with Δ > 0, with half the cell deteriorating by more than 50 points), while US movers split into an unmoved half and a severely deteriorating minority — a bimodality that convergence-to-mean does not produce but heterogeneous filing agency does (US insiders whose new issuer files for them versus the minority who, for whatever reason, file or fail on their own).

Third, and most tellingly, the mechanical objection is the structural thesis in the US case: if measured individual behaviour is dominated by the issuer's filing function, then the measurement "artifact" is the institutional mechanism operating, and its comparative weakness in Canada — where the same design produces near-universal individual movement — is precisely the cross-regime result. What the objection legitimately removes is any reading of the US cell means as individual behaviour change; we do not so read them.

Fourth, the classification-feedback variant is testable directly, and fails: reclassifying every corner-cell origin and destination issuer with the mover's own filings removed leaves the band assignment intact for 92–96% of Canadian and 83–90% of US transitions — the median mover accounts for roughly 7% of their issuer's filings — so the issuers that define the culture gradient are, overwhelmingly, classified by the behaviour of everyone else. (The residual flips concentrate at very small issuers where a single insider is a large share of the record; excluding them would not move any headline estimate.)

4.3 Alternative explanations

Regulatory strictness. As noted, the deadline gradient runs the wrong way: the US regime is stricter yet several times more compliant. Deadline difficulty alone cannot produce the pattern. A subtler version — that Canada's per-transaction-type deadline structure (two to ten days) creates confusion that a flat two-day rule does not — is more interesting and not excluded by our data; it is, however, itself a variant of the institutional argument, since confusion is precisely what a professionalized filing function absorbs.

Enforcement culture. The SEC has repeatedly and publicly enforced Section 16 timeliness, including coordinated sweeps in 2014, 2023, and 2024 (SEC Press Releases 2023-201, 2024-148), while Canadian enforcement of insider-report lateness has been comparatively administrative (OSC Staff Notice 51-726 documents a remediation-oriented review posture). Differential enforcement could depress the US late rate. Two observations limit this alternative, without eliminating it. First, enforcement operates largely through the institutional channel — the 2014 sweep documented by Jackson, Lynch-Levy and Taylor produced spillover improvements at firms that were not themselves targeted, consistent with compliance departments, not individuals, responding to salience. Second, enforcement intensity has no obvious mechanism for producing the transmission gap: harsher penalties should make individuals more careful everywhere, not make their behaviour less sensitive to which company they work at. An enforcement story fits the level gap; it does not fit the contamination attenuation.

Industry and firm-size mix. The Canadian public market contains a large population of small venture-exchange issuers — junior resource and cannabis issuers prominent among them — with limited compliance infrastructure, and our data include no industry or size covariates with which to standardize the comparison — an acknowledged confound (Section 6). Composition surely explains some of the level gap. It explains less well the transmission gap measured within each regime's own culture gradient, and it does not explain why the Canadian Low band — the same quarter of issuers that achieves perfect compliance — produces movers who deteriorate almost universally on arrival at High-culture issuers, while equivalent US movers mostly do not.

Sample composition and the population asymmetry. The Canadian sample excludes 10%-only holders while the US sample retains them (Section 2.2). This alternative is tested directly in Section 3.4: rebuilding the full pipeline under symmetric population definitions — both regimes directors-and-officers-only, and both regimes all-roles — leaves the level gap at 3.5–3.7× and every tested regime-difference significant under both pairings. The population choice does not manufacture either gap.

4.4 Relation to prior literature

The results extend the peer-effects literature from misconduct propagation between firms (Kedia, Koh and Rajgopal, 2015) to compliance-behaviour transmission between firms and individuals, and they qualify the firm-persistence result of Dyreng, Hanlon and Maydew (2008) in an instructive way: their later finding that individual executives carry measurable fixed effects across firms (Dyreng, Hanlon and Maydew, 2010) is the corporate-tax analogue of exactly the question our cross-regime design answers for filing compliance — how much of behaviour travels with the person versus residing in the firm depends on who executes the behaviour, and the Canadian and US regimes bracket the two answers. The findings also connect to the timeliness-as-information literature (Cline and Houston, 2023; Jackson, Lynch-Levy and Taylor, 2022): if late filing is partly strategic, then regimes that route filing through an institutional desk remove not only sloppiness but some of the opportunity for strategic delay — a point with direct bearing on the policy discussion in Section 7.

SECTION 05

The 10%-only holders: a sidecar analysis

The 135,155 post-2010 SEDI filings by insiders whose only reporting relationship is a 10% security holding — 7,661 insiders across 5,588 issuers, excluded from the primary Canadian analysis — provide a useful placebo population, and they deliver a result that cuts against a lazy reading of the Canadian level gap. These holders are more compliant than directors and senior officers: 18.0% of their filings are late against 22.0% for the directors-and-officers population (a −3.9 point difference), with a lower amendment share (5.7% vs 6.7%). Conditional on being late, their delay distribution is similar (median 41 vs 45 days late).

The finding is consistent with the professional-support hypothesis: pure blockholders are disproportionately sophisticated investors — funds, family offices, strategic acquirers — whose block transactions are executed with legal and administrative support, so their filings are effectively institutionally produced even within an individual-filer regime. In other words, the most compliant population on the Canadian side is the one whose filing process most resembles the US institutional default. Directors and officers, by contrast, file frequently, personally, and — at the margin — sloppily. We present this as a descriptive comparison (the populations differ in transaction type, frequency, and wealth, among other things), but it is a second, independent observation pointing at filing agency rather than nationality as the operative variable.

A directly measured US sidecar — 78,970 post-2010 Form 4 filings by 5,977 pure 10% owners across 3,697 issuers, extracted from the working file to mirror the Canadian sidecar — reveals the US image of this finding, and it flips the sign. US 10%-only owners file late 11.7% of the time against 5.9% for US directors and officers: exactly twice the rate. The delay distribution sharpens the contrast. Conditional on being late, US blockholders are late a median of 39 days against 15 for directors and officers, with the gap persisting through the tail (p99 of 2,157 versus 1,163 days) — whereas the two Canadian populations, once late, are nearly indistinguishable (median 41 versus 45 days). US blockholders are the least compliant US population, and they are worse both at the extensive margin (being late at all) and the intensive margin (how late), where Canadian blockholders are the most compliant Canadian population. The reversal is exactly what filing agency predicts. The compliance advantage belongs, in both regimes, to whichever population has institutional filing support — and which population that flips with the architecture. In Canada, no one is covered by an issuer desk, so blockholders' private counsel beats directors' and officers' personal filing habits — but because both populations are professionally capable of filing, their conditional delays are similar. In the US, directors and officers sit inside the issuer's compliance process, while an outside blockholder frequently files through their own arrangements and loses that coverage — and an issuer desk that misses a deadline misses it by days, while an uncovered blockholder who misses one can miss it by months. This also refines, rather than contradicts, the premise of Section 2.2: issuer-desk coverage of US insiders is evidently strong for directors and officers and weaker in practice for outside 10% owners — a nuance that leaves the design choice intact (retaining US 10% owners biases the US sample toward lateness, i.e., against the level gap we report) while sharpening the mechanism. Within each country, holding regulation, enforcement, and industry mix constant, the group holding the better pen files better.