Common LLC problems and how to avoid them: lessons from real clients

70% of the problems we see daily in already-formed LLCs cluster on 5 fronts. Based on our experience with hundreds of LLC owners, these are the most common problems, and how to prevent them.

About 70% of the problems we see daily in already-formed LLCs cluster on 5 fronts: late BOI, missing Form 5472, personal-funds commingling, lapsed Annual Report, and lost Registered Agent.

Based on our experience helping hundreds of LLC owners, these are the most common problems, and how to prevent them. Each one can cost you time, money, or both.

Most common problems

Problem 1: EIN delays blocking everything

What happens: The EIN process takes 4-8 weeks for non-residents. During this time, you can't open Mercury, set up Stripe, or issue invoices with your EIN.

Prevention: Start the EIN process immediately when you form the LLC. At Exentax, we file the EIN application simultaneously with the Articles of Organization. maximizing overlap time.

Problem 2: Mercury account rejection

What happens: Mercury rejects the application due to business type, documentation issues, or country of residence.

Prevention:

Have complete documentation (Articles, EIN letter CP 575, Operating Agreement with Disregarded Entity classification)
Describe your business clearly and accurately
Ensure your industry isn't in Mercury's restricted list
Have an active website or online presence
Work with Exentax. we know what Mercury needs and how to present your case

If rejected, Relay (Thread Bank, FDIC) and Wise Business are alternatives.

Problem 3: Form 5472 missed. $25,000 penalty

That is exactly why at Exentax we keep your calendar tight — you stop thinking about deadlines and we close them before they ever bite.

What happens: LLC owner doesn't know about Form 5472, doesn't file it, receives IRS penalty notice for $25,000 (IRC §6038A).

Prevention: Work with a formation service that includes annual compliance. Never assume you "don't need to file" without confirming with a professional. At Exentax, we file Form 5472 + Form 1120 automatically.

Problem 4: Commingling funds. piercing the corporate veil

What happens: Owner uses Mercury card for personal expenses, pays personal bills from LLC account. Tax time becomes a nightmare; corporate veil is at risk.

Prevention: Absolute rule. Mercury is for business only. Personal expenses from personal account. Every personal transfer from Mercury is documented as a distribution. Use Wallester virtual cards for business subscriptions to keep tracking clean. Use Relay sub-accounts for client-level organization.

Problem 5: BOI Report not filed. $591/day penalty

That is exactly why at Exentax we keep your calendar tight — you stop thinking about deadlines and we close them before they ever bite.

What happens: Owner forms LLC without knowing about BOI Report requirement. Penalty: $591/day for non-compliance, up to $10,000 fine and 2 years imprisonment for willful violations.

Prevention: Ensure your formation service files the BOI Report at formation (within 90 days). At Exentax, it's included in every formation package.

Problem 6: Registered agent lapses. LLC dissolved

What happens: Owner doesn't renew registered agent. State sends notice. If ignored, state dissolves the LLC administratively. Mercury may freeze the account.

Prevention: Use a formation service that includes registered agent renewal as part of annual maintenance. Never let it lapse.

Problem 7: Choosing the wrong state

What happens: Owner chooses Delaware because it "sounds prestigious," then discovers franchise tax. unnecessary for a simple freelancer business.

Prevention: Choose based on actual needs. For most freelancers: New Mexico (no state annual fees) or Wyoming (strongest asset protection (with annual report)).

Problem 8: Not updating platforms after changes

What happens: LLC address, ownership, or bank account changes, but Stripe/PayPal/Mercury/Wise aren't updated. Payments get rejected or complicated.

Prevention: Whenever anything changes in your LLC, update all connected accounts immediately. Also update the BOI Report within 30 days.

Problem 9: Ignoring local tax obligations

What happens: Owner thinks "LLC means 0% taxes" and doesn't declare income in home country. Tax authority investigation follows.

Prevention: Understand that US LLC pays $0 US federal tax, but you MUST declare in your country of residence. Work with both Exentax (US compliance) and a local tax advisor.

Problem 10: Not maintaining records throughout the year

What happens: Tax time arrives and owner has no organized records. Form 5472 preparation becomes expensive and stressful.

Prevention: Monthly routine: download Mercury statements, file expense receipts, track Owner's Draws in a simple spreadsheet. 10 minutes per month saves hours at tax time.

Problem 11: Using Wise as primary account

What happens: Owner keeps entire business treasury in Wise. Wise freezes account during compliance review. Owner has no backup and no FDIC protection.

Prevention: Use Mercury as primary (FDIC insured). Use Wise only for currency conversion. Have Relay as backup. Use Slash for corporate treasury.

Problem 12: Not having a backup account

What happens: Mercury conducts compliance review (normal, routine). Account is temporarily restricted for 1-3 weeks. Owner can't receive payments or pay expenses.

Prevention: Open Relay as backup from day one. Have Wise configured for alternative payment receipt.

Problem 13: FBAR not filed

What happens: LLC owner has US bank accounts with aggregate balance exceeding $10,000 at any point during the year and doesn't file FBAR (FinCEN Form 114). Non-willful penalty: up to $12,909 per violation.

Prevention: File FBAR annually if your US account balances exceed $10,000. At Exentax, we track this and file automatically as part of annual maintenance.

Problem 14: Operating Agreement doesn't meet banking requirements

What happens: Generic Operating Agreement template (from LegalZoom, Inc Authority, etc.) lacks foreign owner provisions, Disregarded Entity classification, or manager-managed structure. Mercury, Stripe, and PayPal reject the application.

Prevention: Use a custom Operating Agreement drafted specifically for non-resident, single-member, Disregarded Entity LLCs. At Exentax, every OA is customized for this specific use case.

Problem 15: Currency conversion losses

What happens: Owner converts USD to local currency through traditional banks charging 2-4% markup plus wire fees of $15-45. On $60,000/year, that's $1,200-2,400 lost to unnecessary fees.

Prevention: Use Wise Business for all currency conversions. Mid-market rate with transparent fees of 0.4-1.5%. On $60,000, you save $600-1,500/year compared to traditional banks.

Problem 16: Not having clear invoicing processes

What happens: Owner sends informal payment requests instead of professional invoices. Clients delay payment, disputes arise, and documentation for Form 5472 is incomplete.

Prevention: Create a professional invoice template with LLC name, EIN, Registered Agent address, Mercury payment details, and clear payment terms (Net 15 or Net 30). Use Mercury Invoicing, Stripe Invoicing, or FreshBooks.

Problem resolution: the complete guide

The "insurance policy" approach

Think of your LLC compliance like insurance: you pay a small amount regularly (maintenance service) to avoid catastrophic penalties:

$25,000 per missed Form 5472
$591/day for late BOI Report
$12,909 per FBAR violation
Account closure and frozen funds from banking issues

The annual cost of proper maintenance is a tiny fraction of any single penalty. That's why every Exentax client sleeps well. knowing every filing is handled, every deadline is tracked, and every platform is properly documented.

Closing out, here's a related piece that sits naturally next to this article: How much does it cost to form a US LLC? Complete cost breakdown helps round off the context.

Legal and regulatory references

This article relies on rules currently in force. Main sources for verification:

United States. Treas. Reg. §301.7701-3 (entity classification / check-the-box); IRC §882 (tax on foreign income effectively connected with a US trade or business); IRC §871 (FDAP and withholding on non-residents); IRC §6038A and Treas. Reg. §1.6038A-2 (Form 5472 for 25% foreign-owned and foreign-owned disregarded entities); IRC §7701(b) (tax residency, substantial presence test); 31 U.S.C. §5336 (Corporate Transparency Act, BOI Report to FinCEN).
Spain. Law 35/2006 (LIRPF), arts. 8, 9 (residency), 87 (income attribution), 91 (CFC for individuals); Law 27/2014 (LIS), art. 100 (CFC for companies); Law 58/2003 (LGT), arts. 15 (anti-abuse) and 16 (simulation); Law 5/2022 (Form 720 penalty regime after CJEU C-788/19 of 27/01/2022); RD 1065/2007 (Forms 232 and 720); Order HFP/887/2023 (Form 721 crypto). And if a notice does land, at Exentax we keep the dossier ready so you reply in hours, not weeks.
Spain–US treaty. BOE of 22/12/1990 (original DTT); Protocol in force since 27/11/2019 (passive income, limitation on benefits).
EU / OECD. Directive (EU) 2011/16, amended by DAC6 (cross-border arrangements), DAC7 (Directive (EU) 2021/514, digital platforms) and DAC8 (crypto-assets); Directive (EU) 2016/1164 (ATAD: CFC, exit tax, hybrid mismatches); OECD Common Reporting Standard (CRS).
International framework. OECD Model Convention, art. 5 (permanent establishment) and Commentaries; BEPS Action 5 (economic substance); FATF Recommendation 24 (beneficial ownership).

Applying any of these rules to your specific case depends on your tax residency, the LLC's activity and the documentation you keep. This content is informational and does not replace personalized professional advice.

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:

How to read the most common LLC mistakes as a stable checklist rather than as anecdotal stories

The most common mistakes that we see on LLC files read more usefully when they're treated as a stable, repeatable checklist than as a collection of anecdotal stories. The recurring root causes — mixed personal and business funds, missing or late Form 5472 filings, no documented separation between the member and the LLC, no Registered Agent renewal — appear again and again across very different profiles, and they're easier to prevent than to repair after the fact.

A short, dated note at the top of the LLC folder that lists the recurring obligations and the date each one was last met turns the same checklist into something the member can review in a few minutes a year, instead of rebuilding it from memory under pressure.

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.

Why most "common problems" trace back to three preventable habits

Most of the recurring problems that show up in LLCs operated from abroad trace back, at the end of a calm review, to three preventable habits rather than to the structure itself. The first is mixing personal and operational expenses on the same payment instruments. The second is leaving the annual maintenance to memory rather than to a calendar. The third is treating the bookkeeping as something to catch up at year end rather than as a steady monthly routine.

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. At Exentax we have closed clients in exactly this spot at zero penalty. Speaking up early pays off — and saves you five figures.

Key takeaways

What follows is the operational view, not the textbook one. We have run this play enough times to know which variables collapse first under scrutiny from a tax authority or a banking compliance team, and that is the order we tackle them in.

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.

The most common LLC problems and how to avoid them before they happen

After years handling non-resident LLCs, the problems we see are always the same four or five. None exotic, all avoidable with planning, all expensive if they materialise. Honest list of what breaks and how to shield it from setup.

Forgetting the annual 5472 + 1120. The most expensive penalty and the easiest to avoid. $25,000 minimum for not filing 5472 when required (single-member LLC with foreign owner and reportable transactions - almost always). Due 15 April, extendable to 15 October with Form 7004. Solution: hire bookkeeping from day 1 including filing. Not "I do it next year when I have time".
Not filing FinCEN BOI Report. Penalty $591/day (capped over $10k). Applies to nearly every new LLC: 30 days from formation to report. Subsequent changes (address change, membership transfer, new manager) have 30 days from change. Solution: include initial BOI in setup and annual change review. That is exactly why at Exentax we keep your calendar tight — you stop thinking about deadlines and we close them before they ever bite.
Mixing personal and LLC money. Breaking patrimonial separation (piercing the corporate veil) lets a creditor sue you personally and removes limited liability. Solution: strict separate account, documented salaries/draws, never use LLC card for personal expenses, monthly bookkeeping with reconciliation.
Not declaring the LLC at residence. Spain (Form 720 if >50k EUR + IRPF by attribution), France (IR + 3916 foreign account), Germany (ESt + AStG if CFC), Portugal (IRS), Italy (IRPEF + RW). Typical sanction: 50%-150% of evaded tax plus interest. Solution: at LLC opening, plan residence declaration with local advisor.

What we are asked the most

If I have not invoiced anything, do I file 5472 anyway? Yes, except very limited exception. Obligation is triggered by "reportable transactions", and almost any movement between owner and LLC (initial capital, loan, withdrawal) is reportable. Default: always file.

Can I fix past years without filing? Yes, via late filing (5472 can be filed late) and, if applicable, delinquent submission programme. Penalty is the same as not filing, but voluntary filing reduces aggressive audit probability.

At Exentax we handle integral compliance (5472/1120 + BOI + bookkeeping + residence advisory) and, when we inherit LLCs with broken history, we regularise first and plan after - order matters.

Legal and procedural facts

On the same topic

What if HMRC, the IRS or my local tax authority asks about my LLC?

It's the question every client raises in the first consultation, and the short answer is: your LLC isn't opaque, and a properly declared structure closes any inquiry in standard forms. Your tax authority can request the state Certificate of Formation (Wyoming, Delaware or New Mexico), the EIN issued by the IRS, the signed Operating Agreement, the Mercury or Wise statements for the year, the Form 5472 plus pro-forma 1120 you filed, and the bookkeeping that reconciles income, expenses and movements. If all of that exists and is delivered in order, the inquiry doesn't escalate.

What tax authorities do pursue, and rightly, is sham ownership (nominees, paper residency) and undeclared foreign accounts. A well-structured LLC is the opposite: you appear as beneficial owner in the BOI Report when applicable (verifiable at fincen.gov/boi), you sign the bank accounts and you declare the income where you actually live. The structure is registered with the state Secretary of State, with the IRS and, when European banks are involved, inside the CRS perimeter of the OECD standard.

The mistake that really sinks an inquiry isn't having an LLC; it's not attributing the income correctly in your domestic return, not declaring foreign accounts when the year-end balance exceeds the local threshold (€50,000 in Spain via Modelo 720; the equivalent FBAR / Form 8938 in the US for residents; T1135 in Canada), and not documenting related-party transactions between the member and the LLC. Those three fronts are worth closing before any request arrives, not after.

## What an LLC does NOT do

- It does not exempt you from tax in your country of residence. If you live in Spain, France, Germany or Portugal, you are taxed there on worldwide income. The LLC organises your US side (zero federal tax for non-resident SMLLC pass-through, absent Effectively Connected Income); it does not switch off your domestic taxation. The income tax is computed on the attributed profit, not on the dividends actually paid.

- It is not an offshore vehicle or a BEPS scheme. It is a US entity recognised by the IRS, registered in a specific state with physical address, registered agent and annual informational filings. Classic offshore jurisdictions (BVI, Belize, Seychelles) leave no public trace; an LLC leaves a trace in five different places.

- It does not protect you if you commingle funds. The pierce the corporate veil doctrine kicks in as soon as a judge sees the LLC and the member behaving as the same wallet: mixed accounts, personal expenses paid from the LLC, no signed Operating Agreement, no bookkeeping. Three suspicious transactions are enough.

- It does not save you social security contributions at home. If you are self-employed in Spain, France or Germany, your monthly social contribution remains identical. The LLC handles the trading side with international clients; your personal contribution is independent.

- It does not exempt you from declaring foreign accounts. Spain residents file Modelo 720 / 721; UK residents, the SA106; Portugal residents, the Anexo J of Modelo 3 IRS; Germany residents, the Anlage AUS. Those obligations belong to the individual, not to the LLC.

At Exentax we cover those five fronts every year alongside the US federal calendar (Form 5472, pro-forma 1120, FBAR, state Annual Report and BOI Report when applicable). The goal is that no inquiry finds a loose end and that the structure withstands a 5-to-7-year retroactive review.

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