Startup mistakes with legal consequences: what each one costs

Most startup legal problems don't begin with a breach. They begin with a postponement. We'll sign the founders' agreement once there's something to split. We'll file the trademark once the product takes off. The freelancer is a friend, no need for a copyright clause. Each of these decisions is reasonable on the day it's made, and almost every one comes back at exactly the moment it costs the most: across the table from an investor, in a buyer's legal due diligence, or in a letter from the tax authority.

This piece is a map. It walks through eighteen mistakes, grouped by the stage where they usually happen, and for each one says what it looks like in practice, why founders make it, and what it actually costs. Almost every one has detailed mechanics - procedures, deadlines, sanctions - in a separate article of ours, which we link to rather than repeat: when a threshold or a sanction changes, the number should live in one place.

Amounts marked as indicative are estimates from practice, not statutory figures - the real cost depends on the specific case.

1. At founding

Co-founders with no written agreement

Two friends register an OOD 50/50 and agree everything verbally, because trust seems enough. Eighteen months later one of them goes back to a corporate job - and keeps their 50%.

The law doesn't stop them. The Commerce Act contains no mechanism that removes or buys back a partner's shares when they stop working for the company, and the right to a share of profit (Art. 133 of the Commerce Act) follows the stake in the capital, not the hours worked. The partner may leave on three months' notice under Art. 125(2) and receive a property share based on the balance sheet - but they don't have to. Meanwhile, at 50/50, any general meeting decision under Art. 137 that needs a majority - appointing a manager, approving the annual accounts, distributing profit - can be blocked.

The result is called dead equity: half the company belongs to someone who doesn't work in it. When you try to raise a pre-seed or seed round, investors see it straight away in the cap table and usually walk. Expulsion under Art. 126 is a general meeting decision in which the partner being expelled doesn't vote, but it requires a written warning and a proven ground - such as failure to cooperate or conduct against the company's interests. The expelled partner can challenge the decision in court and keeps the right to the value of their stake. The procedure is in the co-founder article.

The protection is a founders' agreement signed before anyone has put in an hour of work: a vesting schedule with a cliff, a right to buy back unvested shares, and a deadlock mechanism. The parameters, good/bad leaver and deadlock mechanisms are in the corporate structure article; how vesting is achieved in a Bulgarian OOD, which doesn't recognise reverse vesting, is in the capital-raising guide.

The wrong legal form

The cheapest start is a sole trader (ET) - and the most expensive when something goes wrong. An ET is not a separate legal entity: you answer for the business's debts with all your personal assets - accounts, home, car.

An EOOD or OOD solves the liability problem but creates another one that only shows at the first round. Every share transfer needs notarisation and registration (Art. 129 of the Commerce Act), and an OOD doesn't recognise share classes the way an AD or a DPK does. That makes an option plan, quick angel entries or a SAFE considerably more cumbersome.

Restructuring after the fact - a conversion, a contribution in kind, or a flip to a foreign holding company - costs, by practice estimates, between EUR 3,000 and EUR 15,000 in notarial, registry, valuation and legal fees, and slows the business down by 3 to 6 months. A flip adds an IP transfer, re-signed customer contracts and tax questions.

The comparison of the forms is in the corporate structure article, and the tax cost of a flip - tax on the share swap with no cash received - in the capital-raising guide.

Trading before registration

The first customers often arrive before the company does: custom development, consulting, sales through a website, payments into a personal account.

For the law, though, merchant status (Art. 1 of the Commerce Act) arises from actually carrying on commercial activity as a business, not just from entry in the Commercial Register. There are three consequences. Administrative sanctions for trading without registration, and separate pecuniary sanctions from the tax authority for sales without a fiscal device or approved sales software (SUPTO). Income received personally is treated by the tax authority as the individual's business income - with tax, retroactive social security contributions and statutory interest. And if turnover crosses the VAT registration threshold, the obligation arises for you personally, with VAT charged retroactively and paid out of your own pocket.

The threshold and how turnover is counted changed from 2026 - the current figures in euro are in our tax article. The takeaway is simple: register the company before the first invoice.

2. Intellectual property

Code from a contractor with no IP assignment

This is the mistake that stops deals most often. The startup is negotiating a Series A, and legal due diligence shows the core of the platform was written by a freelancer under a standard contract for services - with no copyright clause. The fund freezes the deal until the rights are sorted out.

The cause lies in the Copyright and Neighbouring Rights Act. Under an employment contract, Art. 14 gives the employer the right to use the code the employee creates. Under a civil contract, Art. 42 applies: without an express assignment clause the copyright stays with the contractor, and the client only gets a non-exclusive right to use the work for the purpose it was commissioned for. And the courts read granted rights strictly - only the rights, territory and term expressly listed (Art. 36).

Once the deal depends on their signature, the freelancer holds a strong hand. By practice estimates, a retroactive assignment can cost EUR 20,000 to EUR 50,000 in extra fees, and if they refuse, rewriting the affected code costs around EUR 30,000 and 6 months of delay.

The clause doesn't need to be complicated, but it does need to be complete. Sample wording:

"The Contractor assigns to the Client the exclusive and unlimited economic copyright in all computer programs, source code, databases, architectures and documentation created in performing this contract, for the entire term of protection under Art. 27 of the Copyright and Neighbouring Rights Act and for the territory of the whole world, including the right under Art. 36 of that Act to modify, adapt, reproduce and further license the rights to third parties, without additional remuneration."

The difference between Art. 14 and Art. 42, and the moral rights that can't be assigned, are in the employment law article; the place of the chain of title in due diligence is in the capital-raising guide.

Open source under the wrong licence

A developer adds a library because it solves the problem in an afternoon. Nobody looks at the licence.

Open source licences fall into two groups. Permissive ones - MIT, Apache 2.0, BSD - allow free use, modification and commercialisation without requiring you to disclose your own code. Copyleft ones - GPL, AGPL - impose the same licence on the derivative software. With the GPL that is triggered when the software is distributed. AGPL version 3 goes further: it is also triggered when the software is provided as a service over a network. For a SaaS product, that means a single AGPL component in the backend can oblige it to make its source code available to everyone using it over the network.

The discovery usually doesn't come from you. An investor or enterprise customer runs the code through licence-audit software, finds the AGPL library and wants it removed before the deal. By practice estimates, the audit and replacement cost between EUR 10,000 and EUR 40,000 in rewriting and testing, plus a delay to the product roadmap. It's far cheaper to have a rule from day one: permissive licences only, a check on every new dependency, and an audit before every round.

The trademark filed after success

A startup trades under one name for two years, builds a user base and invests in marketing. Then a letter arrives: a third party has registered the same or a similar mark for the same classes of goods and services and demands that you stop using it.

Both Bulgarian and EU law apply the first-to-file principle. Rights in an unregistered sign (Art. 12 of the Marks and Geographical Indications Act) are limited and don't protect you against someone else's registration. Rebranding after two years - new domains and profiles, a reworked website and apps, lost organic traffic and conversion - costs, by practice estimates, between EUR 15,000 and EUR 50,000.

Registration costs a fraction of that. The comparison of national and EU registration, the fees, the timelines and the six-month priority right are in our intellectual property article.

3. The team

A civil contract instead of employment

The first developer is hired under a civil contract because it's cheaper and more flexible. Eighteen months later they have a company laptop, working hours, a daily standup and a line manager - and fall out with the company. A complaint to the labour inspectorate is the next step.

Under Bulgarian law what decides is the substance of the relationship, not the title on the document. Fixed working hours and place, equipment supplied by the client, subordination to internal instructions and regular monthly pay with no specific end result are the marks of employment. The inspectorate can declare it with an order under Art. 405a of the Labour Code.

The bill arrives retroactively, for the whole period: the contributions due, including the employee's share, statutory interest on them, compensation for unused paid leave, and a pecuniary sanction for each separate breach. With a team of several people, that's not one fine.

The mechanics of the order and the four criteria the inspectorate applies are in the employment law article. The size of the sanction and the tax and social security side of freelancers are in the tax article.

Dismissal without procedure

A founder lets an employee go with a Slack message over "poor performance" - no request for an explanation, no reasoned order. The employee sues.

Terminating an employment contract is a formal process, and the three typical failures are predictable. Dismissal without notice where there are no grounds for summary dismissal. Disciplinary dismissal without the Art. 193 Labour Code procedure: the employer must ask for a written explanation before imposing the penalty, and without it the court annuls the dismissal without examining the misconduct on the merits. And an order without specific reasons and the particulars required by Art. 195.

When a dismissal is annulled, the employer owes compensation under Art. 225(1) equal to the employee's gross pay for the time they stayed out of work - up to 6 months. Court costs come on top, and the case takes between eighteen months and three years across all instances.

The procedure, deadlines and compensation are in the termination section of the employment law article.

Equity promised verbally

"You'll get 2% of the company when we raise." A key employee accepts a lower salary in exchange for that promise, works for two years and leaves after a dispute.

The verbal promise is almost unenforceable: transferring shares in an OOD requires a written contract with notarisation (Art. 129(2) of the Commerce Act), and proving oral agreements above a certain value through witnesses is restricted by the procedural rules. That doesn't make the problem harmless. The former employee can bring a claim for unjust enrichment (Art. 55 of the Obligations and Contracts Act) or for breach of the arrangement, and a pending dispute is exactly what the investor will find in due diligence.

Equity promises get documented in writing - an option agreement, an ESOP or phantom shares - with a clear vesting schedule and measurable conditions. The employment law side is in the employment law article; vesting is in the capital-raising guide; when the employee's tax arises is in the tax article.

4. Customer contracts

Working without a written contract

The project is agreed by email, the work is delivered, and the client refuses to pay the final invoice because "the functionality doesn't match expectations".

Email has evidential value as an electronic document. But without a structured contract - with a technical specification, an acceptance procedure with a signed handover record, and penalty clauses - the dispute becomes a dispute about what was ordered in the first place. Collecting through the courts means a court fee proportional to the claim, almost certainly a court-appointed software expert, legal fees, and 12 to 24 months of proceedings. For a claim of a few thousand euros the maths often doesn't work - and the client knows it.

If you do work without a full contract, the email trail should contain at least three things: unambiguous approval of the scope of work, an exact final price and payment terms, and written confirmation of acceptance of the result from someone authorised to give it.

The red flags in our supplier contracts article - unilateral price changes, excluded liability - make a useful checklist for your own customer contracts too.

A contract with no intellectual property clause

The same rule from section 2 works in both directions. An agency builds a website with no IP clause - and when the client wants to sell it or change it with another team, the agency asserts copyright claims. The reverse case is more dangerous for a startup: you build a custom solution for an enterprise client without reserving the rights in your underlying technology (background IP), and the client claims it owns all the code and can bar you from using the architecture for other clients.

In both cases the contract wording decides: only the rights expressly listed are granted, and everything not listed stays with the author (Art. 36 of the Copyright and Neighbouring Rights Act). So a custom development contract has to separate clearly what's newly created, which passes to the client, from pre-existing technology, which stays yours and is licensed only as far as needed. The mechanics of assignment under Art. 42 are in the employment law article.

Auto-renewal for consumers

A SaaS startup automatically charges an individual for an annual subscription renewal with no advance notice. The consumer disputes the payment through their bank and files a complaint with the Consumer Protection Commission (KZP).

Between businesses, auto-renewal clauses are valid. Towards consumers, a tacit renewal without a reasonable period to object is an unfair term under the Consumer Protection Act and is void - whether or not the consumer read it. The cost comes twice: a KZP sanction, imposed for each unfair term separately, and chargeback fees on the disputed payments at your expense.

The exact legal basis, compliant wording for the clause and the KZP's real sanctioning practice are in our B2C compliance checklist.

When the deal was only verbal, the question becomes what you can prove - see verbal agreements and how to prove them.

What a contract with a business customer should settle, from the liability cap to penalties and the payment term, is in our article on customer contracts.

5. Tax

A missed VAT registration

The startup grows, turnover crosses the mandatory VAT registration threshold, and the application isn't filed on time. The tax authority picks it up in an audit months later.

The consequences: VAT is charged retroactively on taxable turnover from the moment the obligation arose until the actual registration - and since you didn't charge it to your customers, you pay it out of your own margin. Statutory interest runs on the tax, and the breach itself carries a pecuniary sanction under Art. 178 of the VAT Act.

The trickier registration, though, isn't the threshold one. Registration under Art. 97a of the VAT Act is mandatory before the first payment for a service from a foreign supplier - AWS, Google, Meta, OpenAI - regardless of turnover, and under it you self-assess VAT on the services received. Most startups trigger it with their very first cloud subscription.

The three types of registration, the thresholds in euro and why B2B services abroad don't count are in our tax article.

Personal spending through the company

A family holiday, household shopping, a "business" lunch with no business in it - paid with the company card and booked as an expense. In an audit covering three years back, the tax authority finds them.

This isn't just a disallowed expense. Personal spending paid by the company is treated as a hidden distribution of profit - taxed like a dividend and hit with a separate pecuniary sanction on the amount, plus corporate tax on the disallowed expense and statutory interest for the whole period.

The percentages and legal bases are in the tax authority section of the tax article. The rule is simple: separate personal and company cards, and no expense without an invoice and a clear business purpose.

Dividends instead of social security

The founder of an EOOD works in the company as manager and architect, but isn't registered as self-insured and has no management contract. They live on dividends.

The dividend on its own is lawful and tax-efficient. The problem is that people who put personal work into their own company are subject to mandatory social security - as self-insured persons or under a management and control contract (DUK). In an audit, the tax authority charges the contributions retroactively for the whole period with statutory interest and fines the missing declarations.

The salary-versus-dividend comparison in numbers and the 2026 social security thresholds are in the tax article. The choice between a DUK and self-insurance is in the corporate structure article.

6. Fundraising

A term sheet with a participating liquidation preference

Founders negotiate the valuation, because it's the number everyone talks about. The liquidation preference looks like a technicality.

The maths says otherwise. A startup raises EUR 1,000,000 for 20% with a 2x participating preference. Three years later the company sells for EUR 2,000,000:

• the investor first takes its 2x preference - EUR 2,000,000;
• EUR 0 is left to distribute among the shareholders;
• the investor with 20% takes EUR 2,000,000, the founders with 80% - nothing.

These clauses get signed because of information asymmetry and a focus on valuation. The usual negotiating benchmark is a 1x non-participating preference: the investor chooses between getting its investment back and taking its pro-rata share of the sale. The variants at a bigger exit and the other clauses that move money are in the capital-raising guide.

Advisor equity with no vesting

An experienced mentor gets 1% of the company upfront, with no conditions. After two calls they stop replying.

An inactive shareholder in the cap table is the same dead equity as a departed co-founder, just smaller - and at the next round funds usually want it cleaned up as a condition of investing. Advisor equity is granted under a written agreement with vesting, a cliff and specific duties - number of sessions, introductions to be made. Typical sizes and schedules for advisors are in the vesting section of the capital-raising guide.

Disclosing to investors without protection

A founder presents the product architecture to a corporate venture fund. Six months later the corporation launches its own near-identical product.

Copyright protects the specific code and text, but not ideas, concepts, methods and procedures (Art. 2 of the Copyright and Neighbouring Rights Act). Protection as a trade secret under the Trade Secrets Protection Act requires you to show you took reasonable steps to keep the information secret. And venture funds routinely refuse to sign NDAs for early pitches.

The answer is discipline, not a document: don't disclose source code and unique algorithms at an early stage, mark written materials as confidential, and keep a record of who received what. If the product contains an invention, remember the novelty requirement too - public disclosure before filing can destroy the chance of a patent. Trade secrets as an alternative to patents, and the novelty rule, are in the intellectual property article.

7. Mistakes with an article of their own

A non-compete in the employment contract. A clause barring an employee from working for a competitor after they leave is void when it sits in the employment contract itself - it can't be enforced and no penalty is owed under it. The lawful route - a separate agreement with compensation - is in the employment law article.

An AI feature without a risk assessment. The AI Act regulates the use, not the technology - the same model can be out of scope in one application and high-risk in another, for example in recruitment or lending. And if you modify someone else's model and release it under your own brand, you become a provider with far more obligations. The framework is in the AI Act article.

A platform where users upload content, with no notice mechanism. If users upload content or sell through your product, the Digital Services Act already applies to you - some baseline duties bind even a two-person team. Which duties apply to you is in the DSA article.

Selling software to a bank without preparing for DORA. If you sell software, cloud or data to financial institutions, you're a "third party" to them - and without demonstrated resilience and the right contract clauses they won't buy. What they'll ask for is in the DORA article.

A connected product that locks in the customer's data. If your product has a sensor or your service collects telemetry, under the Data Act the customer can demand the raw data - for free - and for new products access has to be built into the design. The scope and the exceptions are in the Data Act article.

A token marketed as "utility". A token that promises staking income or a share of fees is a financial instrument, whatever the white paper says - which means operating without a licence. How a token is classified is in the MiCA article.

A crowdfunding campaign from an OOD. An EOOD technically can't run an equity campaign, and a cap table with hundreds of investors scares off the next fund. The mechanics are in the equity crowdfunding article.

The map at a glance

Mistake	In depth in
No founders' agreement	Corporate structure
ET or OOD with no growth plan	Corporate structure
Revenue before registration	Tax
Freelancer code with no assignment	Employment law
AGPL component in SaaS	This article
Trademark filed late	Intellectual property
Civil contract instead of employment	Employment law
Dismissal without procedure	Employment law
Equity promised verbally	Capital raising
No written contract with a client	Supplier contracts
Contract with no IP clause	Employment law
Tacit renewal for consumers	B2C compliance
Missed VAT registration	Tax
Personal spending through the company	Tax
Dividends with no social security	Tax
Participating liquidation preference	Capital raising
Advisor equity without vesting	Capital raising
Disclosure without protection	Intellectual property

What to fix first

Solo or a duo (0-6 months). Register an EOOD or OOD before you issue the first invoice, and register under Art. 97a of the VAT Act before the first payment to a foreign cloud provider. Sign a founders' agreement with vesting and a buy-back right. Search the name in the trademark databases and file.

You have a team and first customers. Clean up your intellectual property: an express assignment clause in every civil contract and clear job descriptions in the employment ones. Move anyone who works set hours on your equipment onto an employment contract, and sort out your own social security. Standardise your customer contract - scope, acceptance, limitation of liability, rights in the underlying technology - and watch turnover against the VAT threshold.

You're preparing a round. Run an open source licence audit and replace anything copyleft. Clean up the cap table: written option or phantom agreements instead of verbal promises, and vesting agreements for advisors. Prepare a data room with the corporate, employment and tax documents, and read the term sheet line by line - the liquidation preference before the valuation.

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This article is general information as of September 2026, not individual legal, tax or social security advice. Statutory thresholds, rates and sanctions aren't repeated here but linked to the articles where they are covered and kept up to date. For a specific situation, get advice.

The full picture, stage by stage: starting a startup in Bulgaria - a step-by-step legal guide.