Sell-Side Mandate Fees: Retainer, Success Fee and 2026 Practices

What does a sell-side mandate cost? The five mandate structures, 2 to 5% success fees, retainers and the decisive engagement letter clauses, 2026.

Introduction: what does a sell-side mandate really cost in 2026?

The fees of a sell-side mandate combine two components: a retainer, from a few thousand to 15,000 CHF in Switzerland and generally from 3,000 to 10,000 EUR in France, and a success fee of around 2 to 5% of the sale price depending on the structure retained, degressive with the size of the transaction, often combined with a minimum fee. Five mandate structures coexist, full success fee, mixed retainer and success fee, full retainer, hourly rate and monthly flat fee with success fee, detailed below. The bulk of the total is paid at closing: no sale, no success fee.

This remuneration model is the most discussed and the least documented in M&A advisory: everyone knows its principle, almost nobody publishes its figures. The ranges in this article are drawn from Hectelion's market observations of its competitors' practices, in France as in Switzerland, on the SME and mid-cap segment. They give business owners what they lack most at signing time: reference points.

"A broker is a person who is engaged, in exchange for a fee, either to indicate to the other party an opportunity to conclude an agreement, or to act as an intermediary in the negotiation of a contract.", Article 412 of the Swiss Code of Obligations, definition of brokerage.

Three misunderstandings dominate fee discussions. The first concerns the basis of the success fee, enterprise value or share price, earn-out included or not: differences worth tens of thousands of francs. The second concerns the retainer, perceived as a cost when it is first and foremost a mechanism of mutual commitment. The third concerns the comparison of percentages between advisors, meaningless as long as the scopes of the mandates are not compared.

This article details the components and their ranges at a glance, the five mandate types and their uses, what drives the fees, the exact mechanics of the success fee, how a mandate unfolds, the comparison of advisor types, the five costly mistakes, two worked cases, one Swiss and one French, and finally the ten most frequent questions.

Fees at a glance: components and 2026 ranges

Component	Switzerland (CHF)	France (EUR)	Role
Retainer (commitment fee)	A few thousand to 15,000	3,000 to 10,000	Covers preparation, commits both parties
Success fee	2 to 5% of the price depending on structure, degressive	2 to 5% of the price depending on structure, degressive	Pays for the result, due at closing
Minimum fee	Common below 5 MCHF of price	Common below 5 M EUR of price	Floor of the success fee on small transactions
Disbursements	Rebilled at cost	Rebilled at cost	Data room, travel, documentation

Indicative ranges drawn from Hectelion's market observations of its competitors' practices in France and Switzerland, SME and mid-cap segment, 2026. Excluding VAT.

The overall logic is one of alignment of interests: the advisor earns mainly if the sale completes, and earns more if the price is better. The percentage is degressive because the effort of selling a 40 MCHF company is not ten times that of a 4 MCHF company: small transactions sit towards the top of the percentages, large ones towards the bottom.

The five mandate types: from full success fee to monthly flat fee

Mandate type	Typical uses	2026 observed levels
Full success fee	Startups, business transfers and sales	3 to 5% below 5 MCHF or M EUR of value, degressive beyond
Mixed retainer and success fee	Sales, successions and acquisitions	Success fee of 2 to 4% degressive; retainer from 10,000, milestone-based
Full retainer	Family transfers, acquisitions, valuation, fairness opinion, due diligence	Paid as the project progresses, in several instalments
Hourly rate	One-off expert interventions, occasional advice	Switzerland: 150 to more than 700 CHF; France: 100 to 500 EUR
Monthly flat fee and success fee	Long or uncertain processes, continuous support through to closing	Flat fee of 3,000 to 8,000 CHF or EUR per month, fully deducted from the success fee

Hectelion market observations, 2026. Excluding VAT.

The full success fee mandate pays the advisor only at closing: no fixed payment, everything rests on the result. It is the most frequent structure for startups and for business transfers or sales, with rates of 3 to 5% where the enterprise value or the transaction remains below 5 million, in francs as in euros. The scale is degressive with size: the larger the company, the lower the rate. Its logical counterpart is the advisor's selectivity, who commits resources only to files they consider sellable.

The mixed retainer and success fee mandate is the reference structure for transactions: sales, successions and acquisitions. The success fee, generally degressive with the size of the company, sits between 2 and 4%; the retainer generally starts at 10,000 francs or euros and is triggered by specific milestones of the process, teaser released, information memorandum finalised, offers received, rather than by the calendar. At Hectelion, retainer amounts paid are always deducted from the success fee at closing: the client never pays twice for the same work.

The full retainer mandate applies where the deliverable is not a binary transaction or where independence requires it: family transfers, acquisitions, valuation mandates, fairness opinions, due diligence. Fees are paid as the project progresses, in several instalments defined in the engagement letter. For an equivalent scope, the total amount matches the orders of magnitude of the other structures: the payment schedule changes, the price of the work does not.

The hourly rate, finally, covers assignments that are hard to quantify in advance: one-off expert interventions in a sale or acquisition process, technical opinions, occasional advice. In Switzerland, it runs from 150 CHF to more than 700 CHF per hour in the most technical settings; in France, it generally starts at 100 EUR and reaches around 500 EUR. The right reflex: ask for an estimate of the number of hours and a cap beyond which your approval is required.

The monthly flat fee and success fee mandate combines a fixed fee, billed each month from preparation through to closing, with a success fee due on the result. Unlike the milestone-based retainer, this flat fee is paid on a regular schedule, which smooths the seller's budget and secures the advisor's remuneration on long processes or those whose duration is uncertain at signing. At Hectelion, the entirety of the monthly flat fees collected is deducted from the success fee due at closing, exactly as with the classic retainer: the client never pays twice for the same work. This structure is particularly suited to complex family transfers or sales requiring prior reorganisation, where the mandate's duration is hard to anticipate at signing.

Frame your fees before signing a mandate

A sell-side mandate commits you for months and for significant amounts. Book a free and confidential call: we review your sale project, the scope of mission actually needed and the corresponding fee structure, before any commitment on your side.

Acontos: estimate the value of your company online, free of charge

Before going into detail, note that Hectelion has developed Acontos, an online tool for audit, due diligence and business valuation, powered by Anthropic's Claude Sonnet 5 artificial intelligence and calibrated by Hectelion's methodology. From your financial statements, it produces a first estimate of the value of your shares in a few minutes, free of charge and without retaining any document. Launch the valuation simulator: knowing the order of magnitude of your value before discussing fees means negotiating your mandate in full knowledge, since the success fee is based on the sale price.

What drives the fees: size, complexity, competitive tension

First, the size of the transaction, the primary determinant of the percentage. Degressivity is the rule in France as in Switzerland: a sale below 5 million commonly negotiates between 3 and 5% on a full success fee basis, mixed mandates between 2 and 4%, with large transactions falling below these levels. The minimum fee corrects the equation on small transactions, where a percentage alone would not cover the work involved.

Second, the scope of the mission. A full mandate covers preparation, valuation, information memorandum, documentation, the identification and approach of buyers, the organisation of the competitive process, negotiation and support through closing. A restricted mandate, introduction only or assistance in the final negotiation, logically costs less: comparing percentages without comparing scopes makes no sense.

Third, the complexity of the file. A dispersed shareholder base, a prior carve-out, real estate to separate, an international dimension or reinforced confidentiality all add to the workload. Likewise, a poorly prepared company will require more upstream work, preparation of the accounts, EBITDA normalisation, building of the data room, elements that weigh on the retainer or call for a separate preparation phase.

Fourth, the attractiveness of the target and the competitive tension it allows. A highly desirable company, on which the advisor can organise genuine competition between buyers, fully justifies its success fee: it is competitive tension that drives prices up, far more than bilateral negotiation. Conversely, a narrow file, with a single natural buyer, is handled differently, sometimes with a larger fixed component.

Finally, the country: for an equivalent scope, French retainers are generally lower than Swiss ones, reflecting cost levels, while success fee percentages are comparable on both sides of the border. For a Franco-Swiss group, the real criterion lies elsewhere: the advisor's ability to address buyers in both markets.

Success fee mechanics: calculation basis, degressivity, earn-out

The calculation basis is the most important clause of the mandate, and the most often skimmed. A percentage based on enterprise value or on the share price does not produce the same amount as soon as the company carries debt or cash; an earn-out included in or excluded from the basis moves tens of thousands of francs; a vendor loan, real estate sold separately or management packages complicate the equation further. The engagement letter must define the basis with the precision of a price clause: what the percentage applies to, when each component is due, and what happens if part of the price is deferred or conditional.

Degressivity is most often organised in brackets, in the manner of the historical Lehman formula, now adapted by each firm: a higher percentage on the first millions, decreasing thereafter. Some mandates provide, on the contrary, for an increased percentage beyond a target price, to align the advisor on outperformance: a healthy mechanism when a realistic floor price has been set by mutual agreement, on the basis of a documented business valuation rather than an aspiration.

Payment occurs at closing, on the funds actually received. For deferred components, earn-out, escrow, vendor loan, the balanced practice is to pay the corresponding success fee when the seller collects, not before. Here again, everything plays out in the drafting of the engagement letter.

The engagement letter in 7 clauses: what must be in it

A balanced engagement letter addresses seven points. One, the basis of the success fee, defined with worked examples annexed, as detailed above. Two, the crediting of the retainer against the success fee, with its schedule. Three, exclusivity, bounded by verifiable performance milestones: teaser released, memorandum finalised, indicative offers received. Four, the initial duration of the mandate and its renewal mechanism, express rather than tacit.

Five, the tail clause, the most contentious of the profession and the least discussed at signing: it makes the success fee due if the company is sold, after the end of the mandate, to a buyer introduced or approached during it. Its principle is legitimate, it protects the advisor's approach work against circumvention; its drafting must be bounded, a nominative list of the buyers concerned annexed at the end of the mandate and a limited duration, twelve to twenty-four months in practice. Six, disbursements, rebilled at cost against receipts, with a cap beyond which the client's approval is required. Seven, early termination: notice, treatment of the retainer and of work performed, articulation with the tail clause.

Two reflexes complete the list: have the letter reviewed by your lawyer, a sell-side mandate is a contract like any other, and judge the advisor by their reaction. A professional confident in their value accepts milestones, bounds and worked examples without difficulty; resistance on these points says something.

How a mandate unfolds: where the money goes

The retainer covers the preparation phase, the densest in work: analysis of the company, valuation, drafting of the teaser and the information memorandum, building of the data room, definition of the buyer list. This phase typically lasts six to twelve weeks and conditions everything else: a well-prepared file sells better and faster.

Then comes the market phase: confidential approach of buyers, management of confidentiality agreements, release of the memorandum, collection of expressions of interest and then indicative offers, organisation of management presentations. This is where the advisor's value materialises, in their ability to create and sustain competitive tension between several candidates, as detailed in our guide to the sale process.

The final phase runs from the negotiation of binding offers to closing: exclusivity, buyer due diligence, negotiation of the sale agreement and warranties, satisfaction of conditions precedent. The success fee, paid at closing, pays for the entire journey, whose total duration most often extends from nine to eighteen months. Set against this duration and the result obtained, the fee debate gains perspective: the real subject is not the percentage, it is the final price obtained, net of everything.

Comparing the options: who to entrust your mandate to

Investment banks and large M&A platforms address major transactions, with sizeable teams and minimum fees to match: below a certain sale price threshold, their model simply does not apply. M&A boutiques and independent firms cover the core of the SME and mid-cap market, with fee structures close to those described here and files handled by the partners themselves. Brokers and online marketplaces handle small transactions and goodwill sales, on more standardised terms.

Three criteria discriminate better than the percentage: who will actually work the file, an experienced partner or a junior team; what access to the relevant buyers, sectoral and geographic, the Franco-Swiss dimension being decisive for companies straddling both markets; and what honesty in the initial framing, a serious advisor also saying when a company is not ready to sell, and what must be fixed first, preparation of the accounts, vendor due diligence, structuring.

Hectelion acts as an M&A advisor on sales and transfers of 2 to 500 MCHF, in France and Switzerland, with one methodological particularity: the documented valuation first, the mandate next, so that the fee discussion, like the price negotiation, rests on an objectified basis rather than on hopes.

The impact of AI: lasting downward pressure on advisory prices

Artificial intelligence exerts lasting downward pressure on advisory prices, and this pressure will keep growing. Every step with a strong production component, analysis of the company, first valuation work, drafting of the teaser and the memorandum, documentary research, takes fewer hours than before: the cost base of mandates is falling, and competition gradually passes these gains on to clients. Time-billed components are in the front line, retainers, hourly rates on standard work, preparation packages; marketplaces and platforms amplify the movement on the lower end of the segment. It is worth preparing for: advisory prices will be structurally lower and lower.

The decline is not uniform, however. The success fee resists better, because it is indexed to the result and not to time spent: what AI does not replace, real access to the right buyers, the confidential conduct of the process and the creation of competitive tension, remains what makes the final price. For the seller, the practical conclusion is twofold: demand that AI productivity gains show up in the fixed components of quotes, and keep choosing your advisor for their ability to push the price up, the only criterion that outweighs the fees themselves.

The 5 mistakes that cost money

Mistake 1: Signing a success fee without precisely defining its basis

Enterprise value or share price, earn-out included or not, excess cash, real estate sold separately: every ambiguity in the basis turns into a dispute at closing, at the worst moment. Demand a definition of the basis as precise as a price clause, with worked examples annexed to the engagement letter.

Mistake 2: Treating the retainer as a cost to eliminate

A mandate with no fixed commitment mechanically places your file at the bottom of the advisor's pile, behind those that include one. The retainer is not a comfort margin: it funds the preparation, the phase that determines the final price, and it commits both sides. The right move is not to remove it but to make it creditable against the success fee, a common and balanced practice.

Mistake 3: Comparing percentages without comparing scopes

A 2% "introduction only" often costs more, in degraded final price, than a 4% covering preparation, competitive process and negotiation. The percentage says nothing about the service rendered: compare engagement letters line by line, deliverables, timeline, team assigned, before comparing rates.

Mistake 4: Accepting a long exclusivity without milestones or exit

Exclusivity is legitimate, the advisor invests heavily at the start of the mandate, but it must be bounded: a reasonable initial duration, performance milestones (teaser released, indicative offers received), and an exit clause if the milestones are not met. A long unconditional exclusivity turns a poor choice of advisor into the immobilisation of your sale project.

Mistake 5: Choosing the cheapest advisor rather than the one who will create tension

A success fee point saved is measured in tens of thousands of francs; a well-run competitive process is often measured in millions on the final price. The rational economic criterion is not the cost of the advisor, it is the expected net seller price, fees deducted. That is the whole point of a structured process versus an endured bilateral negotiation.

Case 1: sale of a Swiss B2B services SME at 12 MCHF

A case built for illustration on observed market practices: a Swiss B2B services SME sells for 12 MCHF at the end of a full competitive process. The mandate's fee structure: a 10,000 CHF retainer covering preparation, creditable against the success fee, and a success fee of 3% of the sale price, or 360,000 CHF at closing. Total advisory cost: 360,000 CHF after crediting, or 3% of the price, for a fourteen-month mandate that pitted three binding offers against each other.

The figure takes its meaning against the counterfactual: the spontaneous offer received before the mandate, which had triggered the owner's reflection, valued the company at 9.5 MCHF. The competitive process produced a 2.5 MCHF difference, seven times the fees. This is the typical scenario that justifies the success fee model, and the reason why the percentage alone is a poor selection criterion.

Case 2: sale of a French distribution SME at 4 M EUR

A case built for illustration on the French side: a regional distribution SME sells for 4 M EUR to an individual buyer backed by a fund. Fee structure: a 6,000 EUR retainer, a 4% success fee with a minimum fee of 120,000 EUR, degressivity not applying at this price level. At closing, the success fee comes to 160,000 EUR, the minimum fee remaining moot.

Two lessons. First, the slope of degressivity: at 4 M EUR, 4% is within the French norm; the same company at 20 M EUR would have negotiated towards 2 to 2.5%. Second, the role of the minimum fee: it protects the advisor if the final price disappoints, and it should alert the seller when set far above the success fee expected at the displayed target price, a sign that the advisor doubts that target. Here again, a documented valuation upstream of the mandate avoids mandates built on promises.

The executive's perspective

"The percentage question is always the first one asked, and it is almost always the wrong one. The right question is: what is left for the seller, net of everything, in each scenario? An advisor who creates genuine competitive tension pays for itself, several times over."

"I am wary of mandates with no retainer: they commit no one. The seller believes they won the negotiation, and their file waits behind those of clients who committed their advisor. A reasonable retainer, creditable against the success fee, is the healthiest structure I know."

"Before signing a mandate, have your company valued. Not to set the price, the negotiation will take care of that, but to judge the promises: an advisor who announces a price far above a serious valuation is preparing your disappointment, and their own."

Aristide Ruot, Ph.D., founder of Hectelion

FAQ: the 10 essential questions on sell-side mandate fees

Introduction: what to keep in mind before the questions

A retainer from a few thousand to 15,000 CHF (3,000 to 10,000 EUR in France), a success fee of 2 to 5% depending on the mandate structure, degressive, a minimum fee on small transactions: the ranges are simple, everything plays out in the engagement letter. The ten questions below are those sellers actually ask, with answers based on the Franco-Swiss market observations of 2026.

Q1: Are sell-side mandate fees negotiable?

Yes, within reasonable limits: the structure (crediting of the retainer, degressivity brackets, minimum fee) is more usefully negotiated than the percentage itself. An abnormally low rate should worry you as much as a high one: it signals low advisor investment or hidden costs elsewhere.

Q2: Who pays the fees, the seller or the buyer?

Each party pays its own advisor: the seller pays their sell-side mandate, the buyer pays their acquisition advisors and their due diligence. The fees of the sell-side mandate are owed by the seller who signed it, individual or company depending on the structure of the transaction, a point to settle with your tax advisor.

Q3: Is the retainer creditable against the success fee?

It is the most common and most balanced practice: the retainer commits both parties during preparation, then is deducted from the success fee at closing. A non-creditable retainer is mainly justified on files with exceptionally heavy preparation; it must then be made explicit as such.

Q4: On what basis is the success fee calculated?

This is THE clause to negotiate: share price or enterprise value, treatment of cash and debt, inclusion or not of the earn-out, the vendor loan and assets sold separately. The rule of balance: the percentage is paid on what the seller actually collects, at the moment they collect it.

Q5: Is mandate exclusivity mandatory?

It is the normal counterpart of the advisor's initial investment, but it must be framed: limited initial duration, performance milestones and an exit clause. Non-exclusive mandates exist, particularly for introductions, with a logically lower commitment from the advisor.

Q6: What is a minimum fee and should you accept it?

It is the floor of the success fee, common and legitimate on transactions below 5 million where the percentage alone would not cover the work. It becomes a warning signal when set far above the success fee expected at the target price: the advisor is telling you, implicitly, that they do not believe in that price.

Q7: Are there fees if the sale fails?

The retainer remains earned by the advisor, that is its function, and disbursements incurred are due. Some mandates provide for an indemnity if the seller withdraws the company from sale or concludes directly with a buyer who was introduced: read these clauses closely, they are normal in principle and sometimes excessive in drafting.

Q8: Are sale fees tax deductible?

The treatment depends on who sells and who pays: company or shareholder, share deal or asset deal. Fees borne by the selling holding company are generally treated as transaction costs; their deductibility and offset against the capital gain differ between France and Switzerland. Validation by your tax advisor is essential before signing.

Q9: Do you also need a lawyer, and at what cost?

Yes: the M&A advisor drives the process and the economic negotiation, the lawyer drafts and negotiates the legal documentation, sale agreement and warranties. These are two distinct and complementary budgets; the legal fees of an SME sale run to tens of thousands of francs or euros depending on complexity, usually billed on time spent.

Q10: Why is the percentage degressive with size?

Because the advisor's effort does not grow proportionally with the price: selling a 40 million company does not require ten times the work of a 4 million company. Degressivity preserves the alignment of interests without producing remuneration disconnected from effort, and the bracket thresholds are negotiated in the engagement letter.

Estimate the value of your company with Acontos, Hectelion's online simulator

To extend this reading with a concrete figure, Hectelion provides Acontos, its online tool for audit, due diligence and business valuation. Powered by Anthropic's Claude Sonnet 5 artificial intelligence and calibrated by Hectelion's methodology, it reads your accounts, normalises EBITDA, applies real sector multiples and rebuilds a net debt bridge to estimate the value of your shares in a few minutes. Launch the free valuation simulator: the success fee is calculated on the sale price, so you might as well know what order of magnitude you are talking about before signing a mandate.

Conclusion: the right mandate is judged on the net seller price, not the percentage

The fees of a sell-side mandate hold no mystery once the components are laid out: a commitment retainer from a few thousand to 15,000 CHF (3,000 to 10,000 EUR in France), a success fee of 2 to 5% depending on the mandate structure, degressive and payable at closing, a minimum fee on small transactions, disbursements at cost. The two cases show it: 3% on a Swiss sale at 12 MCHF, 4% on a French sale at 4 M EUR, levels consistent with the market's degressivity.

The rational decision criterion lies elsewhere, however. An advisor is chosen for their ability to prepare the file, create competitive tension and defend the price, with the difference produced measured in multiples of the fees, as in the Swiss case where the process returned seven times its cost. A well-conducted fee discussion therefore focuses on the engagement letter, basis, scope, milestones, crediting, more than on the rate: that is where the net seller price is protected, the only figure that counts in the end.

Summary of the article

The fees of a sell-side mandate combine a retainer, from a few thousand to 15,000 CHF in Switzerland and 3,000 to 10,000 EUR in France, a success fee of 2 to 5% of the sale price depending on the mandate structure, degressive with size, a minimum fee common below 5 million, and disbursements at cost. Five structures coexist: full success fee (3 to 5% below 5 million, typical of startups and business sales), mixed retainer and success fee (2 to 4%, retainer from 10,000 triggered by milestones and, at Hectelion, always deducted from the success fee), full retainer (paid as the project progresses, suited to family transfers, valuations, fairness opinions and due diligence), hourly rate (150 to more than 700 CHF in Switzerland, 100 to 500 EUR in France) and monthly flat fee with success fee (3,000 to 8,000 CHF or EUR per month, fully deducted from the success fee at closing, suited to long or uncertain processes).

Fees vary with the size of the transaction, the scope of the mandate, the complexity of the file, the attractiveness of the target and the country. The decisive clauses are not the rate but the basis of the success fee, the crediting of the retainer, the exclusivity milestones, the tail clause and the treatment of deferred price components. The five costly mistakes all stem from a negotiation focused on the percentage at the expense of the engagement letter.

Artificial intelligence is putting lasting downward pressure on the time-billed components of advisory fees, while the success fee resists because it is indexed to the result. The model pays for the alignment of interests: well chosen, the advisor produces a price difference that far exceeds their cost, the Swiss case gives the measure, and the right trade-off is always made on the expected net seller price, fees deducted, never on the headline rate.