Uncharged “Structuring” Withdrawals Are Intrinsic Evidence of Payroll-Tax and Insurance-Premium Fraud Schemes (and Implicit-Bias Instructions Are Not Required Where Voir Dire and Neutrality Instructions Suffice)

I. Introduction

In United States v. Giang (1st Cir. Apr. 22, 2026), the Court of Appeals for the First Circuit affirmed Lilian Giang’s convictions for four counts of failing to collect or pay over employment taxes, in violation of 26 U.S.C. § 7202, and one count of mail fraud, in violation of 18 U.S.C. § 1341.

Giang owned and ran Able Temp Agency (“Able”), a Massachusetts staffing business. The government’s theory was that Able (1) paid workers “off-the-books” cash beyond what payroll records reflected, (2) underreported payroll to the IRS via Form 941 filings (generated from Able’s bookkeeping system), and (3) underreported payroll to its workers’ compensation insurer, Travelers, thereby reducing both employment taxes and insurance premiums.

On appeal, Giang challenged: (1) admission of evidence that she withdrew cash in amounts just under $10,000 (suggesting evasion of bank reporting rules), (2) refusal to give an “implicit bias” jury instruction, (3) alleged flaws in jury instructions on tax duties and good faith/willfulness, and (4) the sufficiency of evidence supporting the “use of the mails” element of mail fraud.

II. Summary of the Opinion

Structuring-related evidence admitted: Evidence that Giang repeatedly withdrew cash just below $10,000 was relevant and admissible; it was “intrinsic” to the charged tax and fraud scheme, so Rule 404(b) did not apply; and Rule 403 did not compel exclusion.
No implicit-bias instruction required: The trial judge’s voir dire (explicitly addressing Giang’s Vietnamese origin and need for an interpreter) and standard neutrality instruction substantially covered the concern.
No subcontractor instruction required: Giang did not lay an evidentiary foundation for the theory that workers were subcontractors, so the court properly declined the requested instruction.
Good-faith instruction error was harmless: The instruction risked suggesting that any “purpose of deceiving others” negated good faith, even if unrelated to tax willfulness; however, the error was harmless beyond a reasonable doubt given the trial record.
Mail fraud sufficiency affirmed: Testimony about Travelers’ mailing practices and the pattern of annual premium-adjustment notices supported both actual mailing and foreseeability; Giang failed to show “clear and gross injustice” under the unpreserved-sufficiency standard.

III. Analysis

A. Precedents Cited

1. Standards of review and evidentiary gatekeeping

United States v. Díaz-Rosado (857 F.3d 116): Set the lens for recounting facts after a jury trial—viewing sufficiency-relevant evidence in the light most favorable to the government.
United States v. Santana-Avilés (120 F.4th 7): Provided the preserved-evidentiary-objection standard—abuse of discretion—used to review the admission of the cash-withdrawal/reporting-threshold evidence.
United States v. Monteiro (871 F.3d 99) and United States v. Mare (668 F.3d 35): Emphasized the exceptional deference owed to district courts under Rule 403 balancing; reversal is “rare” and reserved for “extraordinarily compelling circumstances.”
United States v. Weadick (15 F.4th 1) and United States v. Walsh (928 F.2d 7): Supported the court’s point that weaknesses or alternative innocent interpretations generally go to weight, not admissibility.
United States v. Mehanna (735 F.3d 32): Reinforced that evidence need not be excluded merely because it supports multiple plausible interpretations.

2. “Intrinsic evidence” versus Rule 404(b) prior-bad-acts evidence

United States v. Epstein (426 F.3d 431): Anchored the key doctrinal move—evidence intrinsic to the charged crime is not governed by Rule 404(b).
United States v. Souza (749 F.3d 74): The opinion’s central analogy. In Souza, uncharged fraud was intrinsic to explaining the “events leading up to” a structuring charge and intent to evade reporting requirements. Giang applies Souza’s logic in reverse: uncharged structuring is intrinsic to explaining a payroll-tax evasion scheme and intent to conceal.
United States v. Fazal-Ur-Raheman-Fazal (355 F.3d 40): Supplied the formulation (quoted in Souza) that intrinsic evidence includes acts forming the “necessary description” of events leading up to the crime or going to an element of the offense.

3. Jury instructions: requested instructions, bias, preservation, and harmless error

United States v. Figueroa-Lugo (793 F.3d 179) and United States v. McLellan (959 F.3d 442): Provided the three-part test for refusing a requested instruction and framed harmless-error analysis for incorrect instructions on essential elements.
United States v. Díaz-Arias (717 F.3d 1) and Correia v. Fitzgerald (354 F.3d 47): Supported the conclusion that general impartiality instructions plus targeted voir dire can sufficiently mitigate bias concerns, making a more specific instruction nonessential in the “ordinary case.”
United States v. Coleman (149 F.4th 1): Recently affirmed that trial judges may address implicit-bias issues through voir dire and instructions without employing specific materials (there, a video), reinforcing discretion in methodology.
United States v. Teixeira (62 F.4th 10) and United States v. Castillo (981 F.3d 94): Informed the court’s “practical view” of whether Giang preserved her objection to the instructions, focusing on whether the judge understood the objection.
United States v. Jadlowe (628 F.3d 1): Provided the “two-tiered” review framework for preserved claims of instructional error (de novo for legal error; abuse of discretion for adequacy/clarity).
United States v. Powers (702 F.3d 1), United States v. Ramos-Paulino (488 F.3d 459), and United States v. Angiulo (897 F.2d 1169): Set and applied the rule that a defendant receives a theory-of- defense instruction only if the evidence supplies a foundation; and the defendant bears the burden of identifying that supporting evidence.
Boyde v. California (494 U.S. 370): Cautioned that jurors do not parse instructions with lawyers’ precision, supporting the panel’s willingness to recognize instructional risk in the “good faith” language.
United States v. Paredes-Rodriguez (160 F.3d 49), United States v. Baldyga (233 F.3d 674), and Davignon v. Clemmey (322 F.3d 1): Guided harmless-error review by requiring consideration of the full record and whether the instruction likely affected the verdict.

4. Tax “willfulness,” ignorance-of-law principles, and good faith

Bryan v. United States (524 U.S. 184): Explained the general rule that ignorance of the law is no excuse, and recognized tax law’s distinctive willfulness requirement due to technical complexity.
Cheek v. United States (498 U.S. 192): Supplied the controlling definition of tax “willfulness”—knowledge of a legal duty and intentional violation—and framed good-faith misunderstanding as a defense.
United States v. Dockray (943 F.2d 152): Noted that Cheek’s willfulness standard does not apply to mail fraud; the panel nonetheless assessed harmlessness under the higher Cheek standard.

5. Mail fraud: sufficiency, causation/foreseeability of mailing, and “in furtherance”

United States v. Woodward (149 F.3d 46): Provided the baseline sufficiency standard (any rational trier of fact).
United States v. Falcón-Nieves (79 F.4th 116): Applied because Giang did not preserve her sufficiency claim, raising the bar to “clear and gross injustice.”
United States v. Tavares (844 F.3d 46): Supplied the elements of mail fraud, including use of the mails in furtherance.
United States v. Hebshie (549 F.3d 30): Provided the detailed mailing-element framework: the defendant must “cause” use of the mails (including reasonably foreseeable mailings), and the mailing must be “incident to an essential part of the scheme,” broadly construed.
United States v. Morrow (39 F.3d 1228): Supported foreseeability where insurance-fraud submissions predictably trigger “criss-cross” mailings typical of insurer claim/audit processes.
United States v. Pimental (380 F.3d 575) and United States v. Bruckman (874 F.2d 57): Clarified that the defendant need not foresee a particular mailing; it is enough that some mail use is reasonably anticipated in the scheme’s ordinary course.

B. Legal Reasoning

1. Why “structuring-like” withdrawals were admissible (and not governed by Rule 404(b))

The panel upheld admission of evidence that Giang repeatedly withdrew cash just under $10,000—conduct associated with evading Currency Transaction Reports under the Bank Secrecy Act (as referenced via United States v. Morales-Rodríguez). Even though Giang was not charged with structuring, the First Circuit concluded:

Relevance: The pattern (numerous sub-threshold withdrawals, sometimes multiple in a day, and a behavioral change after a teller explained the reporting rule) permitted an inference of deliberate avoidance; disputes about intent went to weight, not admissibility.
Intrinsic-evidence classification: Using United States v. Souza as the blueprint, the panel treated the withdrawals as part of the “necessary description” of how the off-books payroll operated and how it was concealed—directly relevant to intent and knowledge for both the tax and fraud theories.
Rule 403: Given the evidence’s explanatory power for the scheme and the deference mandated by United States v. Monteiro, the court found no “extraordinarily compelling circumstance” justifying reversal.

The practical doctrinal takeaway is that, in the First Circuit, the “intrinsic evidence” label can encompass financial behavior that looks like an uncharged regulatory crime (structuring) when it functions as a concealment mechanism tightly interwoven with the charged fraud/tax offenses.

2. Implicit bias instruction: “substantially covered” can be satisfied by targeted voir dire plus neutrality instructions

Giang sought an instruction modeled on Massachusetts Supreme Judicial Court language addressing subconscious bias. The First Circuit did not reject the value or correctness of such instructions, but held that the trial court’s approach met the McLellan test because the subject was “substantially covered”:

The court’s voir dire explicitly flagged Giang’s Vietnamese origin and need for an interpreter and asked whether those facts would impair fair consideration.
The final charge instructed jurors to decide the case “regardless of any personal likes or dislikes, opinions, prejudice, or appeals to sympathy” and based solely on evidence.

Relying on United States v. Díaz-Arias, Correia v. Fitzgerald, and United States v. Coleman, the panel treated this as sufficient mitigation in the “ordinary case,” while expressly reserving that an implicit-bias instruction may be warranted in other contexts.

3. Defense theory instruction on “subcontractors” requires an evidentiary foundation

Giang argued the jury should have been instructed that employers do not withhold/pay the same employment taxes for subcontractors as for employees—an attempt to inject reasonable-doubt or good-faith misunderstanding.

Applying United States v. Angiulo and United States v. Ramos-Paulino, the court held she did not meet her burden to identify record evidence supporting the theory. A single tax form listing “Subcontracted Services” was overwhelmed by contrary proof: Able’s client contracts stating workers were Able employees; representations to Travelers that there were no subcontractors; absence of 1099 filings; and Giang’s own testimony suggesting she anticipated employer tax obligations.

4. “Good faith” language risked diluting Cheek willfulness, but the error was harmless on this record

The court recognized the danger in instructing that a defendant cannot act in good faith “if she also acted with the purpose of deceiving others,” because—through a juror’s lay reading (cf. Boyde v. California)—that could be taken as negating good faith based on any deceit, even deceit unrelated to the legal-duty/intent inquiry demanded by Cheek v. United States.

Nonetheless, applying United States v. McLellan and record-sensitive harmless-error principles from United States v. Paredes-Rodriguez and Davignon v. Clemmey, the panel held the error harmless beyond a reasonable doubt because the trial record did not present unrelated deceit that might have misled the jury, and evidence of willfulness was strong (including concealment-signaling withdrawal patterns and concealment from the payroll operator).

5. Mail fraud “use of mails”: business-practice proof and foreseeability despite electronic options

Giang attacked the mail fraud conviction on the third element (use of the mails). Under United States v. Hebshie, the government could prove mailing by showing Giang caused reasonably foreseeable mailings and that the mailing was “incident to an essential part” of the scheme.

The panel held that a Travelers witness’s testimony about standard mailing practices, coupled with evidence of annual premium-adjustment notices, was enough for a rational jury to find mailing and foreseeability—even though Travelers also offered electronic access. Foreseeability did not require anticipation of a particular letter (per United States v. Pimental and United States v. Bruckman), only that some mail use would reasonably occur in the scheme’s ordinary course.

Because Giang failed to preserve the sufficiency issue, United States v. Falcón-Nieves required her to show “clear and gross injustice,” a standard she could not meet.

C. Impact

Expanded practical reach of “intrinsic evidence”: The opinion strengthens prosecutors’ ability in payroll-tax and insurance-premium fraud cases to admit “structuring-like” withdrawal patterns (even without a structuring charge) as narrative-and-intent evidence outside Rule 404(b)’s framework, so long as the withdrawals are woven into the mechanics of concealment.
Implicit bias instruction litigation: Giang is likely to be cited for the proposition that explicit implicit-bias instructions are discretionary and that “substantial coverage” can be achieved via targeted voir dire and standard impartiality instructions—though the panel’s caveat leaves room for defendants to argue case-specific necessity.
Instructional-error strategy: The harmlessness holding underscores the importance of building a record showing how an arguably overbroad “deceit” concept could latch onto non-criminal conduct; absent such a record, appellate courts may treat the risk as theoretical.
Mail fraud mailings in an electronic era: The decision reinforces that availability of electronic delivery does not defeat foreseeability of mailed communications where business practice includes regular mailings, especially in insurer audit/premium adjustment processes.

IV. Complex Concepts Simplified

Structuring: Breaking up cash transactions to avoid the bank’s obligation to report cash activity over $10,000. Giang was not charged with structuring, but her withdrawal pattern was used as circumstantial proof of concealment and intent.
Intrinsic evidence: Evidence that is part of the story of the charged crime—necessary to explain how the scheme worked or to prove an element like intent—so it is not treated as “other acts” evidence under Rule 404(b).
Rule 404(b): Generally bars using “other bad acts” to show propensity (“she’s the kind of person who does this”) but permits them for specific purposes (intent, knowledge, etc.) if the rule applies.
Rule 403: Allows exclusion of relevant evidence if unfair prejudice substantially outweighs probative value; but appellate courts give trial judges substantial discretion here.
Tax “willfulness” (Cheek): The government must prove the defendant knew of a specific legal duty and intentionally violated it; sincere good-faith misunderstanding can negate willfulness even if the belief is unreasonable.
Mail fraud “use of the mails”: The defendant need not personally mail anything; it is enough that mailing was a reasonably foreseeable part of carrying out the scheme and was incident to an essential step.

V. Conclusion

United States v. Giang affirms that uncharged “structuring-like” cash withdrawal patterns can be admitted as intrinsic, scheme-explanatory evidence in payroll-tax and related fraud prosecutions, bypassing Rule 404(b) and surviving Rule 403 scrutiny when closely connected to concealment and intent. It also confirms that implicit-bias concerns may be adequately addressed through targeted voir dire and standard neutrality instructions, that theory-of-defense instructions require a real evidentiary foundation, and that mail-fraud mailings can be proven through routine-practice evidence and foreseeability even where electronic communications are available.