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Turning a Daily File of Returned IRA Contributions Into a Controlled, Auditable Reversal Run

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Thread AI Editorial

September 28, 2026

A leading U.S. retirement services provider

Each morning, a treasury operations team works through a bank's list of rejected IRA contributions, finding each original deposit across three systems and keying the same reversal into two of them. Lemma now carries each row from report to reversal once, stops on ambiguous or anomalous deposits, and leaves a record of every decision.

Impact so far

Figure

What it means

Source

48 / 69

rows cleared for straight-through reversal on a real-volume day

Pilot test, tokenized file

~4 min

of manual research and re-keying per row today

Team-reported baseline

1 → 2

one carried record populates both reversal systems, with no re-typing

Pilot design

0

postings chosen by a language model; matching is deterministic

Pilot control

An arduous, fragile process

When a participant funds an IRA by ACH, the firm receives provisional credit from its bank. If the debit bounces (for insufficient funds, a closed account, a stopped payment, etc.) the bank pulls the money back and the firm's account is out of balance with the participant's contract until someone reverses the original deposit.

That someone works from a fixed-width report pulled from a legacy archive each morning. A typical day runs ~50 to ~70 rows and can reach ~180. For each row, an analyst looks up the participant, searches a funds repository for the original posting, confirms the reversal with the right reason, then opens a remittance ledger and types the same contract, amount, dates and reason in again. At ~4 minutes a row, a 65-row day is about an hour and a half of careful copy-and-paste, and every keystroke is a chance to reverse the wrong deposit.

The process had also become fragile. The team is small and mostly new to the role, the written procedure had been re-certified year after year without substantive change, and much of the judgment lived with a few long-tenured people. The goal was a control that holds no matter who is on shift.

The exceptions are the job

A script that clicks through screens would handle most rows and quietly get the rest wrong. Exception examples include, but are not limited to:

  • Look-alike postings. Two deposits with the same contract, amount and date that differ only by bank routing number. Picking one needs evidence, not a guess.
  • Notices of change. Some rows are bank notices with no money attached. They are handled elsewhere and must never trigger a reversal.
  • Restricted accounts. If a row belongs to someone on the treasury team, it has to go to an authorized person instead of the analyst on duty.
  • Weekend files. Monday's report can carry several processing dates, which changes the search window and which systems apply.

Lemma provides an end-to-end solution

Thread AI built the process as a single Lemma Worker following the team's own sequence: detect, research, reverse, notify. The pilot runs against Thread-hosted simulations of the report archive, participant lookup, funds repository and remittance ledger, rebuilt from screens the team shared, so it can be re-pointed at live systems later with minimal change.

1

Ingest and archive.

Pull the day's report, check the trailer totals, save the source file and send it to the pay-in team unchanged.

2

Research each row.

Parse every line, look up the participant, search both systems for candidates and map the bank return code to the correct reversal reason.

3

Review and approve.

An analyst sees every row sorted into four queues and approves before anything is written.

4

Reverse, verify, report.

Enter approved reversals in both systems, confirm them by inquiry, reconcile report to repository to ledger and email the run summary.

The four review queues:

  • Eligible: exactly one matching posting in each system. Pre-filled, ready to approve.
  • Manual: ambiguous or missing match. Copy-ready values and a note field; the analyst decides.
  • Hold: restricted account. Routed to an authorized reviewer; the rest of the day keeps moving.
  • Excluded: notices of change and zero-dollar rows, logged with the reason and never reversed.

Tested on three days: what the reviewer sees

The team handed over one real report, tokenized before it left the firm. Thread AI paired it with two designed days that stress the controls.

Test day

Rows

Total

Eligible

Manual

Hold

Excluded

Real-volume day, tokenized from a live report

69

$57,882

48

17

0

4

Exception sampler, every failure mode in one file

12

$3,515

3

7

0

2

Restricted-account day

6

$1,755

3

0

3

0

On a day the pilot hasn't seen, the Worker still parses, classifies and orders every row and hands the analyst a structured worksheet with copy-ready values. That is the shape the process would take on day one against live systems.

How Lemma did it

1

Deterministic where money moves.

Matching, amounts, dates and reason codes run on explicit rules. The Worker never asks a model to choose a posting or invent a reversal reason, and it refuses rather than guesses.

2

People hold the authority.

Handoffs put approval, exceptions and restricted accounts in front of the right person, and reviewer corrections to the reason mapping are logged so the rules improve.

3

Audit by default.

Every search, candidate count, decision, write and confirmation lands in an append-only event log with recordings of each system session, ready for control testing.

What's next: from simulation to the live systems, quantified

Thread AI works with customer stakeholders to establish the unique success criteria for their use case. Examples include but are not limited to:

  • Wrong-posting selection percentage
  • Number of return codes mapped without a person
  • Number of reversals written against the wrong record, or twice
  • Percentage of rows reaching a recorded final disposition
  • Time to complete the daily file

In production the Worker runs on a schedule, pulls the report straight from the archive, sends it from the firm's own mailbox and enters reversals in the real funds repository and remittance ledger. Classification, review and the audit trail would stay as they are. The same detect, research, reverse, notify pattern would then extend to the adjacent return types the team handles: after-tax annuity and institutional ACH rejects, returned checks and wires.

Tell us about your process.

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Method and sources

The pilot runs on synthetic and tokenized data inside Thread-hosted simulated systems, with no connection to any client system. Figures marked ~ are estimates or team-reported baselines.