Justify source of funds on a second banking KYC round

75% of cases when you provide statements covering the last 6 months and a signed service contract with a client. Mercury, Wise or your processor suddenly asks for additional documentation on the origin of your funds. It is not suspicion, it is a regulated periodic review. How to prepare narrative, document package and response to close in a single round.

A second KYC round at Mercury, Wise or Relay is resolved favourably in 75% of cases when you provide statements covering the last 6 months and a signed service contract with a client.

If you have had your LLC for a while and Mercury, Wise or your payment processor suddenly asks for additional documentation on the origin of funds, you are not alone. It is one of the requests that generates the most anxiety, and almost always one of the easiest to resolve well if approached with order.

The key: it is not a suspicion of anything. It is a regulated periodic review every regulated financial institution applies to active clients. What decides how the review ends is not what you have, it is how you present it.

What a second KYC round actually is

A periodic KYC review is the process by which the institution re-verifies:

Who the beneficial owner of the account is.
The nature of the business operating it.
Where the funds passing through come from.
That the observed pattern matches the information declared at opening.

Triggered by:

Cumulative volume above internal thresholds.
Pattern change in movements.
Standard periodic renewal (every 12-36 months by profile).
Specific information the institution wants to update.

Receiving a second round does not mean something is wrong. It means the account has become active or relevant enough to be reviewed in detail.

What you will typically be asked

The usual package:

Updated identification of the beneficial owner.
Articles of Organization updated.
EIN Confirmation Letter or 147C.
BOI Report confirmation.
Signed Operating Agreement.
Description of the business: what the LLC does, who you invoice, in what countries.
Income justifications: representative invoices, key contracts, processor statements.
Origin of initial funds (if the question is about capital contributions).
Tax filings of the most recent year in some cases.

What looks like 10 separate documents is really one question: does your declared activity match what the account shows?

Guiding principle: coherent narrative

Institutions are not looking for traps. They look for coherence between what you said at opening, what your BOI shows, what your statements show, and what you say now. When the four match, the review closes fast.

So step one of any KYC response is not gathering documents: it is reviewing your own narrative and confirming the documents you will submit support it without contradiction.

Orderly procedure

Step 1. Read the email carefully

Most requests are specific: 4-7 documents with a deadline (typically 7-14 days). Do not respond until you have read every line.

Step 2. Gather your current package

Before generating anything new, check what you already have updated: Articles, EIN letter, OA, BOI confirmation, passport and proof of address current, 5-10 representative invoices, contracts with major clients.

Step 3. Prepare a one-page business description

This is what most differentiates a solid response from a mediocre one. One page covering:

What the LLC does: clear words.
Who it sells to: client type, typical countries, model (B2B/B2C, recurring/project).
How it charges: gateways, terms, currencies.
How much it invoices: monthly or annual ranges.
Where initial funds came from if any (BO's capital, prior savings).

A clear description preempts most questions.

Step 4. Justify origin of funds with typical cases

Professional services income: representative invoices + contracts + statements showing receipts.
SaaS or subscription income: Stripe/Paddle dashboard exported + payouts reconciled.
E-commerce income: Shopify/Amazon dashboard + payouts + supplier invoices.
Initial capital contributions: source personal account statement + concept aligned with "Capital Contribution".
Crypto operations: exchange history + on-chain records if applicable + coherent tax stance.

What does NOT work: explanations without documents, scattered screenshots, vague descriptions.

Step 5. Send the complete package in a single submission

Better one ordered submission than parts over several days. Compliance works in review blocks: each reopen restarts the read.

The package ideally includes a brief introductory email enumerating attachments, in what order, and to what question each part responds.

Step 6. Maintain availability

After sending, the institution may ask for clarifications. Replying within 24-48h on those clarifications is the difference between fast close and a process that drags on for weeks.

What NOT to do

Respond hastily, without coherence, trying to "get it over with". Almost always generates a second and third round.
Move money "for relief" during the review. Any atypical movement during a review complicates it.
Lie or exaggerate the activity. The review cross-checks with statements; divergence is immediate.
Change the address or any profile data while the review is open.
Ignore the email and wait. Most common consequence: unilateral account closure with a window to withdraw funds.

When professional support pays off

Three situations where professional support easily pays for itself:

High volumes (hundreds of thousands or millions per year) where review is exhaustive.
Multi-country or multi-currency operation with many counterparties requiring structured explanation.
History with prior incidents (closures, suspensions).

In other cases, a personal response well prepared with the procedure above is enough.

How we approach it at Exentax

At Exentax we accompany KYC rounds regularly. First we review your own narrative and available documentation, then prepare the complete package in standard format (index, business description, ordered justifications), and if appropriate draft the response cover. Typical close is in a single round.

If you have received a request and want to validate the response before sending, book a free initial session through our booking page. It is worth a professional review before pressing "send".

A balanced banking stack: Mercury, Relay, Slash and Wise

There is no perfect account for an LLC. There is the right stack, where each tool plays a role:

Mercury (operated as a fintech with partner banks (Choice Financial Group and Evolve Bank & Trust primarily; Column N.A. on legacy accounts), FDIC via sweep network up to the current limit). Main operating account for non-residents with strong UX, ACH and wires. Still one of the most proven options to open from outside the US.
Relay (backed by Thread Bank, FDIC). Excellent backup account and for envelope-style budgeting: up to 20 sub-accounts and 50 debit cards, deep QuickBooks and Xero integration. If Mercury blocks or asks for KYC review, Relay keeps your operations running.
Slash (backed by Column N.A. (federally chartered, FDIC)). Banking built for online operators: instant virtual cards by vendor, granular spend controls, cashback on digital advertising. The natural complement when you manage Meta Ads, Google Ads or SaaS subscriptions.
Wise Business (multi-currency EMI, not a bank). To collect and pay in EUR, GBP, USD and other currencies with local bank details and mid-market FX. Does not replace a real US account but is unbeatable for international treasury.
Wallester / Revolut Business. Wallester provides corporate cards on a dedicated BIN for high volume. Revolut Business works as a European complement, not as the LLC's main account.

The realistic recommendation: Mercury + Relay as backup + Slash for ad operations + Wise for FX treasury. This setup minimizes block risk and reduces real cost. At Exentax we open and configure this stack as part of incorporation.

Next steps

Now that you have the full context, the natural next step is to map it against your own situation: what fits, what doesn't, and where the nuances depend on your residency, your activity and your volume. A quick review of your specific case usually saves a lot of noise before taking any structural decision.

Banking and tax facts worth clarifying

Fintech and CRS information evolves; here is the current state:

Before going further, put numbers on your case: the Exentax calculator compares, in under 2 minutes, your current tax bill with what you would carry running a US LLC properly declared in your country of residence.

> Free consultation, no strings attached

Notes by provider

Mercury operates with several federally chartered partner banks and FDIC coverage via sweep network: mainly Choice Financial Group and Evolve Bank & Trust, with Column N.A. still in some legacy accounts. Mercury is not itself a bank; it is a fintech platform backed by those partner banks. If Mercury closes an account, the balance is typically returned by paper check mailed to the account holder's registered address, which can be a serious operational problem for non-residents; keep a secondary account (Relay, Wise Business, etc.) as contingency.
Wise ships two clearly different products: Wise Personal and Wise Business. For an LLC you must open Wise Business, not the personal account. Important CRS nuance: a Wise Business held by a US LLC sits outside CRS because the account holder is a US entity and the US is not a CRS participant; the USD side operates via Wise US Inc. (FATCA perimeter, not CRS). In contrast, a Wise Personal opened by an individual tax-resident in Spain or another CRS jurisdiction does trigger CRS reporting via Wise Europe SA (Belgium) on that individual. Opening Wise for your LLC does not bring you into CRS through the LLC; a separate Wise Personal in your own name as a CRS-resident individual does report.
Wallester (Estonia) is a European financial entity with an EMI/issuing-bank licence. Its European IBAN accounts are within the Common Reporting Standard (CRS) and therefore trigger automatic reporting to the tax administration of the holder's country of residence.
Payoneer operates through European entities (Payoneer Europe Ltd, Ireland) that are also in scope for CRS for clients resident in participating jurisdictions.
Revolut Business: when paired with a US LLC, it operates under Revolut Technologies Inc. with Lead Bank as its US banking partner. The account delivered is a US account (routing + account number); no European IBAN is issued to a US LLC. The European IBANs (Lithuanian, Belgian) belong to Revolut Bank UAB and are issued to European clients of the group. If you are offered a European IBAN tied to your LLC, confirm exactly which legal entity holds that account and which regime it reports under.
Zero tax: no LLC structure delivers "zero tax" if you live in a country with CFC/tax transparency or income attribution rules. What you achieve is no double taxation and correct reporting at residence, not elimination.

Legal & procedural facts

FinCEN and IRS reporting requirements moved recently; the current state is:

BOI / Corporate Transparency Act: your LLC is NOT required to file (a competitive advantage). After FinCEN's March 2025 interim final rule, the BOI Report obligation was narrowed to "foreign reporting companies" (entities formed OUTSIDE the US and registered to do business in a state). A US-formed LLC owned by a non-resident does NOT file the BOI Report: one fewer filing on your calendar, less paperwork, and a cleaner structure than ever. If your LLC was formed before March 2025 and you already filed BOI, keep the acknowledgement. The regulatory status can change again: we monitor FinCEN.gov on every filing and, if the obligation comes back, we handle it at no extra cost. Current status verifiable at fincen.gov/boi.
Form 5472 + pro-forma 1120. For a Single-Member LLC owned by a non-resident, the final regulations of Treas. Reg. §1.6038A-1 (in force since 2017) treat the LLC as a corporation for 5472 purposes. Procedure: pro-forma Form 1120 (header only: name, address, EIN, tax year) with Form 5472 attached. It is filed by certified mail or fax to the IRS Service Center in Ogden, Utah, not e-filed via standard MeF. Due date: April 15; extension via Form 7004 to October 15. Penalty: $25,000 per form per year, plus $25,000 per additional 30 days of non-filing after IRS notice.
Substantive Form 1120. Only applies if the LLC has filed a check-the-box election to C-Corp (Form 8832): it then pays 21 % federal corporate tax and files a substantive 1120. A standard disregarded LLC does not file a substantive 1120 and does not pay federal corporate tax.
EIN and notice. Without an EIN you cannot file 5472 or BOI. The IRS does not warn before imposing penalties; you find out when an EIN is flagged or a later filing is rejected. Breathe: at Exentax this is routine, we bring you up to date and the next review closes in one round, no drama.

Balanced banking stack: Mercury, Relay, Slash and Wise

Read this section as a checklist with teeth: each point flags a real failure mode we have seen in cross-border LLC files. Skip none of them - most reassessments and account closures we clean up later trace back to one of these items.

Justifying source of funds in banking KYC: the "second round" almost nobody prepares

First round KYC passes with passport and address. The second round - arriving at 3-9 months with the first significant inflow - is where 30% of accounts fall. It is the "we want to understand where this money comes from" phase. Here is what the bank wants to see and what disqualifies an answer.

What they will ask. Source of Wealth (how you built your wealth overall) and Source of Funds (specific origin of money flowing in today). Typical documents: tax returns of the last 2-3 years, sale contracts of prior assets (company, property), bank statements showing accumulation, contracts of clients generating current income.
What passes the filter unchallenged. Linear traceability: tax return year X shows income, origin bank shows accumulation, incoming transfer from identified client with service contract and invoice issued by your LLC. Every euro has paper behind it. This is what compliance wants to close the case in 48 hours.
What triggers an alert. Recent cash deposits, transfers from third-party accounts without justified relationship, crypto converted without documented on-chain traceability, "family loans" without notarised loan contract and lender's tax return. Each can freeze the account until resolved.
When to prepare. Before the first inflow >25,000 EUR/USD, not after the bank's request. Having a digital folder with returns, contracts, statements and certifications ready means responding in 24 hours; without them, 3-6 weeks and possible closure.

What we are asked the most

Is crypto converted to fiat problematic? Yes, unless full on-chain traceability: own wallets, identifiable transactions, tax return for the year the gain was generated and the conversion. Without this, almost every bank flags it as risk and asks for heavy additional documentation.

What if funds come from a company sale years ago? Passes the filter provided you have: sale contract, share cancellation deed, statements from the original bank, tax return for the year (with gain declared) and traceability to the current account.

At Exentax we prepare the Source of Wealth/Funds dossier before the first significant operation: documents, coherent narrative and sworn translation where applicable - so that the second round does not freeze your operations.

Legal and procedural facts

What they will typically ask you for

The numbers and the calendar matter - get either wrong and the rest unravels.

Step 1. Read the email calmly and in detail

Field note from running this for clients month after month: the rule is straightforward, the execution is where it breaks. Plan the operational side before the legal side.

Step 2. Compile your current package

Step 3. Prepare a one-page business description

Most of the avoidable damage we see in this exact point comes from skipping the documentation step, not from the underlying tax logic.

What a second-round KYC actually checks

A second KYC round is rarely the bank doubting you personally. It is a

periodic process the compliance team runs when an account profile and

its real movements stop matching: an LLC opened with a "advisory,

low-volume" stated use that now receives marketplace payouts, or a

member listed as Spanish tax resident whose card spend looks centred

in another jurisdiction. The bank is updating its model of the

client, and the documents they ask for are aimed at confirming that

the model still fits.

Three buckets cover most second-round requests:

Once the question is read in those three buckets, the answer becomes

a short, structured paper rather than a stack of disconnected files.

Three real cases we ran with clients

A bilingual designer LLC received a second-round request after a

spike in EUR payouts from a marketplace. The cleanup was a one-page

narrative naming the marketplace, the typical client country mix,

the payout cadence, and three sample invoices. No new structure, no

new account, no drama. The compliance team marked the file complete

within ten business days.

A advisory LLC with a single large institutional client got a

second-round letter the week the first invoice cleared. The answer

was a copy of the master services agreement, the corresponding wire

trace, and a short note explaining that the client expected

quarterly invoicing of similar size. The relationship continued

without any change to the account.

A services LLC operating from Florida received a request after a

large internal transfer between member-owned accounts. We re-titled

that movement explicitly as a member draw, attached the corresponding

ledger entry, and added a forward-looking note on how member draws

would be handled going forward. The bank closed the request and the

client kept the operational rhythm.

Mistakes that turn a calm review into an ugly one

Sending PDFs without a cover note. Documents alone read as evidence

for an unstated thesis; banks want the thesis in one paragraph

first, then the evidence.

Re-explaining the LLC structure from scratch when the bank already

has it. Anchor the answer in what changed since onboarding, not in

what they already filed.

Mixing personal and business documents in the same upload. Each

upload should be a tight, named bundle.

Promising future behaviour and then doing the opposite. Banks

reread the file; consistency is what shortens the next review.

Source-of-funds one-pager template

Member background: nationality, tax residence, professional

history (two lines).

LLC purpose: stated activity, country mix of clients, monthly

expected revenue band.

Capitalisation: how the initial funds entered the LLC and from

where.

Operational rhythm: typical inbound and outbound patterns over a

representative quarter.

Forward note: any expected change in the next 12 months.

We treat the second-round KYC as a normal hygiene event rather than a

threat. Done well, it is the single best reinforcement of the LLC's

banking history and the cheapest insurance against future blocks.

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