“Big‐Number, Simple Math” – Seventh Circuit Clarifies that Voluminous Calculations Alone Do Not Convert a Lay Summary Witness into an Expert
Commentary on United States v. Brian Fenner & Dennis Birkley, 84 F.4th ___ (7th Cir. 2025)

Introduction

United States v. Fenner & Birkley arose from a complex automobile-lien fraud in which a towing-company owner (Fenner) and his financier (Birkley) manipulated Indiana’s mechanic’s-lien statute to strip secured creditors of their interests in roughly one hundred vehicles. After conviction on seventeen counts of mail fraud, wire fraud, money laundering and conspiracy, both defendants appealed. Their principal appellate complaints concerned:

• Whether two Federal Rule of Evidence issues – (i) the admissibility of massive spreadsheet testimony from an FBI forensic accountant and (ii) the scope of intent testimony from an FBI case agent – required a new trial;
• Whether an unredacted, inculpatory statement by Birkley violated Fenner’s Sixth-Amendment right to confrontation;
• The legality of the restitution order and an ex-post-facto challenge.

The Seventh Circuit (per Judge Kolar) affirmed in full, crafting a notable clarification on how far a lay “summary” witness may go without satisfying Rule 702’s expert requirements. It also refined the plain-error framework for unobjected Bruton/Confrontation issues in multi-defendant trials.

Summary of the Judgment

1. Rule 701 vs. Rule 702 – “Big‐Number, Simple Math.” The court held that FBI accountant Kathryn Kanetzke’s testimony – which digested “tens of thousands” of banking pages into bottom-line figures and inferences (e.g., “$1 million gross receipts,” “Birkley funded bankruptcy fees,” “no auction payments ever made”) – remained lay opinion because it employed only elementary addition/subtraction on case-specific records. The sheer volume of data did not transmute her into an expert.

2. Agent Graham’s Intent Testimony. Even if some commentary about motives treaded close to prohibited intent opinions, any error was harmless given overwhelming record corroboration.

3. Confrontation Clause / Bruton. Admission of Birkley’s out-of-court statement was reviewed for plain error. The panel assumed (without definitively deciding) that the statement might be “suggestive” but found no reasonable probability of prejudice, especially after Fenner himself adopted the same “floor-plan” explanation at trial.

4. Ex Post Facto. No violation existed because defendants were prosecuted under federal fraud statutes, not retroactively under the revised Indiana lien law.

5. Restitution. The $49,045.84 award – representing creditors’ unrecovered lien balances and remedial costs – was affirmed; defendants offered no concrete contrary figures.

Detailed Analysis

A. Precedents Cited and Their Influence

• United States v. Lopez, 870 F.3d 573 (7th Cir. 2017) – baseline abuse-of-discretion standard for evidentiary rulings.
• United States v. Christian, 673 F.3d 702 (7th Cir. 2012) – distinction between expert and lay testimony from the same witness.
• United States v. Davis, 53 F.4th 833 (5th Cir. 2022) – collecting circuits that allow “repetitive arithmetic” as lay testimony; the panel adopted its rationale.
• Bruton v. United States, 391 U.S. 123 (1968) and progeny (Richardson, Gray, Samia) – framework for evaluating co-defendant confessions.
• United States v. Stockheimer, 157 F.3d 1082 (7th Cir. 1998) – example where an inculpatory statement was admissible because it became incriminating only when coupled with other evidence.
• Greer v. United States, 593 U.S. 503 (2021) – clarified plain-error prongs post-Rehaif; invoked for Confrontation analysis.
• Restitution caselaw: United States v. Anderson, 866 F.3d 761 (7th Cir. 2017); United States v. Griffin, 76 F.4th 724 (7th Cir. 2024).

Each precedent was deployed to establish two doctrinal pivots: (i) that Rule 701 allows lay witnesses to “do the math” so long as no specialized methodology is introduced, and (ii) that post-trial Confrontation challenges without objection face a nearly insurmountable prejudice requirement under Greer.

B. Legal Reasoning of the Court

1. Rule 701 Boundary. The panel focused on method, not magnitude. Although Kanetzke handled colossal datasets, her tools never left first-grade arithmetic. Because her conclusions were anchored exclusively in documents already in evidence, they were “rationally based on perception” and helpful to the jury – satisfying Rule 701(a)-(c). The court contrasted expert testimony that relies on specialized models or industry know-how (White on Medicare “reasonable costs”).
2. Intent Testimony. Agent Graham’s occasional statements about defendants’ motives risked Rule 701(c) violation, but any misstep was harmless in light of voluminous independent proof (emails, bogus auction notices, unusual hours, etc.). Harmlessness inquiry examined whether the government’s case would be “significantly less persuasive” absent the opinions.
3. Bruton / Plain Error. The court undertook the four-step Olano/Greer test. Without deciding whether admitting the statement was erroneous, the panel rested on prong-three (no reasonable probability of a different outcome) and prong-four (no effect on fairness/integrity). Factors: Fenner echoed the same facts, evidence was overwhelming, and objections were strategically waived.
4. Ex Post Facto & Restitution. The mechanic-lien statute was merely background conduct; the indictment charged federal fraud. Restitution was upheld because creditors were “directly harmed” and figures were supported by PSR exhibits; defendants offered no rebuttal evidence.

C. Impact on Future Litigation

• Practical Evidentiary Impact. Prosecutors (and civil litigants) in the Seventh Circuit can now rely on financial-analyst or case-agent witnesses to summarize voluminous financial data without triggering Rule 702 hurdles, provided the testimony stays within basic arithmetic and case-specific record interpretation.
• Checklist for Trial Counsel. Parties should:
  • Scrutinize whether summary testimony introduces industry concepts or specialized methodologies. If it does, expertise must be disclosed.
  • Formally object at trial to preserve Confrontation errors; Fenner demonstrates how difficult post-verdict relief is under plain-error review.
• Bruton Nuances. The decision underscores that “suggestive but non-facial” co-defendant statements are unlikely to obtain reversal absent timely objection.
• Restitution Guidance. Defendants carry the burden to introduce alternative loss figures; bare denials will not suffice.

Complex Concepts Simplified

• Lay vs. Expert Testimony – A lay witness speaks from personal perception and common sense; an expert uses specialized training or scientific techniques. The line turns on methodology, not job title or volume of data.
• Summary Witness (Rule 1006) – When records are too voluminous for the jury to digest, a witness can provide a distilled chart or narrative, but must rely on admissible underlying documents.
• Bruton Problem – In a joint trial, one defendant’s confession that overtly implicates the other cannot be shown to the jury unless the second defendant can cross-examine the declarant. Neutral redactions or limiting instructions normally solve the issue; failure to object relegates review to the demanding “plain error” standard.
• Plain Error Review – A four-step test: clear error, plainness, prejudice (reasonable probability of different result), and whether the error seriously affects judicial integrity. Missing any prong defeats relief.
• Mandatory Victim Restitution Act (MVRA) – Requires full repayment of victims’ actual losses, including unpaid loans or costs incurred to mitigate the fraud. The court may rely on the Presentence Report unless defendants show it is unreliable.

Conclusion

United States v. Fenner & Birkley offers two principal takeaways:

1. Evidentiary Clarification. The Seventh Circuit cements the notion that quantitative volume alone does not elevate lay summary testimony into expert testimony. Courts, practitioners, and juries may thus rely on non-expert witnesses to perform large-scale but simple math without Daubert gatekeeping.
2. Stringent Plain-Error Barrier. Where counsel fails to object, obtaining reversal on Confrontation grounds is exceptionally difficult; defendants must show actual prejudice and an affront to the system’s integrity.

Beyond its immediate facts, the decision streamlines the prosecution of complex financial fraud, providing a blueprint for employing summary witnesses while respecting defendants’ confrontation rights. Attorneys should absorb these evidentiary guardrails early in case strategy to avoid stumbling on appeal.