The short answer
A law firm's value is best expressed as a supportable range built from maintainable earnings after paying every working principal a market salary, not a single multiple quoted without qualification. Fee-based rules of thumb circulate in the profession — a fraction of annual fee revenue, sometimes expressed as "cents in the dollar" of billings — and they persist because they are quick and because they roughly track how smaller sole-practitioner practices have historically changed hands. But a rule of thumb prices revenue, not earnings, and it says nothing about who the revenue actually belongs to. An earnings-based approach — maintainable earnings after a fair market wage for every working principal, multiplied by a multiple that reflects size, practice-area mix, principal dependence and the quality of the client base — is the more defensible methodology for anything beyond a very small file-transfer sale, and it is the approach a valuation prepared for a related-party transfer, a small business CGT concession claim or a partner buy-in needs to be able to show its working on. The two methods can produce very different answers for the same practice, and reconciling them — rather than picking whichever is more flattering — is the substantive work.
Fee-based rules of thumb versus earnings multiples
The fee-based rule of thumb treats goodwill as a percentage of gross annual fees, with the percentage set by practice area, location and file quality — conveyancing and standard wills-and-estates work has historically traded toward the lower end of any quoted range, contested litigation and no-win-no-fee personal injury books toward the bottom or not at all, and steady commercial or property files toward the upper end. The method's appeal is that fee revenue is easy to verify from practice-management or trust accounting records. Its weakness is structural: two practices billing the same fees can have wildly different profitability, wildly different principal-dependence and wildly different WIP quality, and a percentage-of-fees figure treats them as identical. An earnings-based approach — typically capitalisation of maintainable earnings, cross-checked against comparable transaction multiples where genuinely comparable evidence exists — starts from normalised profit rather than top-line billings, so it naturally reflects overheads, non-billable partner time, associate leverage and the actual cash the practice throws off after every working owner is paid a market salary for the hours they bill. For any matter with a related-party dimension, a tax concession claim, or a value that needs to survive scrutiny, the earnings-based method should be the primary analysis, with the fee-based rule of thumb used only as a sense-check on the conclusion — not the other way around. Where the fee-based rule of thumb and the earnings multiple diverge sharply, that divergence is itself the finding: it usually means the practice's WIP quality, principal dependence or expense structure is materially different from the comparables the rule of thumb was built on, and the valuation needs to say why.
Why maintainable earnings is harder to pin down in a law firm than it looks
Maintainable earnings is the profit a law firm could reasonably be expected to sustain under new ownership once every working principal is paid a fair market salary for the hours they actually bill — and normalising to that figure is not a mechanical add-back exercise. The starting point is what each working principal actually bills and collects versus what they would cost to replace with an employed senior solicitor doing the same billable work — the gap between a partner's profit share and a market-rate replacement salary is often the single largest adjustment in the file, and it is also the adjustment vendors most often resist. Non-billable time matters just as much: practice management, business development, mentoring junior staff and professional body involvement all consume partner hours that never appear on an invoice, and a valuation that only prices billable hours understates what a buyer actually has to fund. Locum and associate cover costs, professional indemnity insurance premiums (which move with practice area and claims history and are rarely trivial for litigation-heavy firms), continuing professional development obligations, and run-off cover considerations on any change of principal all sit inside the true cost structure. The output of this work is a maintainable earnings figure the practice could reasonably be expected to sustain under new ownership with a fairly remunerated team in place — not the figure that happens to appear in the most recent set of financial statements.
Work in progress and lock-up: the asset most owners forget to price
In many law firm sales, WIP and debtors are the largest single component of the deal, and they are also the component most likely to be handled badly. Work in progress — time recorded but not yet billed, and in some matters disbursements advanced but not yet recovered — is not automatically worth its book value. Its realisable value depends on how far advanced the underlying matters are, whether the client relationship and the file itself transfer to the buyer or stay with a departing principal, and how collectable the eventual bill will be once someone unfamiliar with the file has to complete and invoice it. Aged debtors carry a parallel problem: fees billed but not collected lose value the longer they sit, and a buyer pricing lock-up (the combined WIP-to-cash cycle) will typically apply a discount to face value to reflect completion risk, write-off risk and the time cost of collection. Two broad structures are seen in practice. Under a transfer arrangement, the buyer takes on responsibility for finishing and billing the WIP, and the outgoing owner is paid an agreed share as matters resolve and cash is actually collected — this can realise closer to full value but leaves the vendor exposed to the buyer's collection performance and creates an ongoing financial relationship after settlement. Under an upfront purchase, the buyer pays at settlement for WIP and debtors at a negotiated discount to face value, which gives the vendor certainty and a clean break at the cost of a lower price. Litigation files — particularly no-win-no-fee or conditional-fee personal injury matters where the fee is contingent on an outcome that has not yet occurred — sit outside both structures comfortably, because the WIP has no guaranteed realisable value at all until the matter resolves; these files are more often priced as a separate, heavily discounted negotiation than folded into a standard goodwill-plus-WIP formula. Any valuation prepared for a related-party transfer or CGT purpose needs to state which structure applies, how WIP and debtors were valued, and what discount to face value was applied and why.
Tax treatment of WIP and debtors on transfer
The tax treatment of WIP and trade debtors on a practice sale is a matter for the vendor's and purchaser's tax advisers, and it varies with how the sale is structured and the accounting method the practice uses — this is not an area a valuation report opines on. What a valuation does need to do is value WIP and debtors as a discrete asset class within the overall enterprise value, separately from goodwill, so that however the sale agreement or transfer document ultimately allocates consideration between goodwill, plant and equipment, and WIP/debtors, the allocation has an evidenced value behind each component rather than an arbitrary split. Where a practice is restructuring — moving from a partnership to an incorporated legal practice, or admitting a lateral partner via an equity buy-in — the same discipline applies: WIP and debtors need their own supportable value, distinct from the goodwill figure, because the two behave completely differently under both accounting treatment and realistic realisation risk.
Personal goodwill versus institutional goodwill, by practice area
The single question that does more to set a law firm's transferable value than any other is: when the principal walks out the door, does the client follow them? Personal goodwill attaches to an individual practitioner's name, relationships and reputation, and it does not survive a change of ownership — a buyer is not acquiring it, whatever the fee-based rule of thumb implies. Institutional (or practice) goodwill attaches to the firm itself: its brand, referral network, systems, employed team, panel appointments and client base, and it is what actually transfers. The mix between the two varies enormously by practice area. Conveyancing and standard property transactions tend to carry the most institutional goodwill of any legal practice area — clients are typically referred by real estate agents or come through repeat corporate panel work rather than a personal relationship with a named solicitor, the work is systemised, and a well-run conveyancing practice with a stable referral base is genuinely one of the more transferable legal assets in the market. Commercial and corporate practice sits in the middle: institutional relationships with panel appointments, insurers or corporate clients can transfer well, but a practice built around a small number of long-standing client relationships personally held by one partner is closer to a personal-goodwill practice regardless of its formal structure. Family law and criminal defence sit toward the personal-goodwill end — clients typically engage a specific lawyer at a difficult and personal moment in their life, referral is heavily reputation-driven, and much of what a buyer would be paying for often does not survive the seller's departure unless there is a genuine multi-partner team with independently held referral relationships. Litigation more broadly, and particularly plaintiff personal injury and no-win-no-fee practice, adds contingent-fee realisation risk on top of the personal-goodwill question, which is why these files are frequently valued and negotiated separately rather than folded into the headline goodwill figure. A valuation that does not test which category a given practice — or even a given partner's book within a multi-partner firm — actually falls into is not doing the work the file needs.
Succession sale, lateral acquisition, or orderly wind-down: three different value questions
The same practice can produce three quite different numbers depending on the transaction it is actually facing, and conflating them is a common source of disputes between retiring partners and their successors. A succession sale — where an incumbent partner sells to an existing associate, a junior partner, or the practice itself over an agreed handover period — usually realises closer to the earnings-based value, because the buyer already has the client relationships, systems knowledge and referral network in place; the transition risk that discounts an external sale is largely absent, which is precisely why succession sales are often structured as vendor-financed arrangements paid from future earnings rather than a lump sum at completion. A lateral acquisition — where another firm buys the practice, or a partner and their team, to acquire a client base, a specialisation or a geographic footprint — prices institutional goodwill and the durability of referral relationships most heavily, and the acquirer will typically build in earn-out or retention mechanisms tied to client retention over twelve to twenty-four months, because the single biggest risk in a lateral deal is clients or key staff leaving during or shortly after the transition. An orderly wind-down — where a sole practitioner or small partnership closes rather than sells, files are transferred or returned to clients, and remaining WIP is billed out over a run-off period — is not really a sale at all in the goodwill sense; the value realised is largely the collection of outstanding WIP and debtors at a heavy realisation discount, plus whatever plant and equipment is worth, with goodwill typically written down close to nil because there is no ongoing entity for it to attach to. A retiring principal who assumes their practice has a straightforward sale value, without first establishing which of these three pathways is actually available to them, is often the one most surprised by the eventual number.
Regulatory transfer requirements that shape how the deal has to be structured
A law firm sale cannot be executed the way a typical trading business sale is, because the practice sits inside a regulated profession with its own transfer mechanics. Every principal or legal director handling client money must hold a current Australian practising certificate authorising receipt of trust money, and a buyer who is not yet appropriately certificated cannot simply step into that role at settlement — timing the transfer against practising certificate status and any conditions attached to it is a threshold structuring question, not a formality to sort out afterward. Trust account handling is the area with the least room for error: trust money cannot be dealt with outside the trust accounting rules of the relevant state or territory's legal profession legislation, client trust ledgers need to be reconciled and either transferred to the incoming practice's trust account or properly disbursed before completion, and the outgoing practice typically has statutory notification obligations to its regulator (the state law society or legal services board, depending on jurisdiction) around ceasing to hold trust money or changing authorised signatories. Professional indemnity insurance and run-off cover need to be addressed for the outgoing principal's period of practice, separately from whatever cover the incoming owner arranges going forward. Where the practice operates as an incorporated legal practice, the transfer may also involve a change of directors and authorised principals that has its own notification timeline. None of this changes the underlying economic value of the practice, but it does mean a law firm sale agreement typically needs longer lead times, more sequencing conditions and closer coordination with the relevant regulator than a comparable trading-business sale — and a valuation prepared without regard to these mechanics can understate the practical execution risk a buyer is pricing into their offer.
When the number carries a tax position
Law firm goodwill features regularly in CGT events — a partner retiring and being bought out, a lateral partner admitted via equity purchase, a sole practice incorporating into an incorporated legal practice, or a related-party transfer within a family succession plan. For these matters the relevant standard of value is market value as defined in IVS 104 and consistent with the willing-but-not-anxious principle from Spencer v Commonwealth (1907), which is the basis the ATO's market valuation guidance works from. A report prepared to that standard also follows APES 225 Valuation Services, the professional standard governing how CA ANZ, CPA Australia and IPA members conduct and disclose valuation engagements. Where small business CGT concessions under Division 152 of the ITAA 1997 are in view, the maximum net asset value test requires the net value of CGT assets of the taxpayer, connected entities and affiliates to be $6m or less just before the CGT event, and the active asset test under s 152-40 turns on whether the goodwill and other assets are genuinely used in carrying on the practice. Where the transfer is not at arm's length — a partnership restructure, an admission at a value set by the partners rather than tested against the market — market value substitution under s 116-30 can apply, and the documented evidence behind the stated value is what the position rests on if reviewed. Prismi is not a registered tax agent and does not provide tax, legal or financial advice; concession eligibility, deal structure and the trust account and practising certificate mechanics above belong with the practice's accountant and lawyer, working from the valuation evidence. What a valuation contributes is a methodology-tested, evidence-documented position — prepared with the ATO's market valuation expectations in mind so it is defensible if reviewed, not represented as pre-approved by anyone.
What a law firm valuation costs and how long it takes
Prismi's Essential report (from $1,495 + GST) suits a straightforward single-methodology matter — a small file-transfer sale or a simple share transfer — and is delivered in 10–14 business days. The Comprehensive report (from $3,995 + GST) is typically the right tier for a practice sale, lateral acquisition or partner buy-in that needs dual-methodology cross-checking and normalised-earnings analysis, delivered in 15–25 business days. The Defensible Valuation File (from $8,995 + GST), delivered in 25–35 business days, is the level for small business CGT concession claims, contested partner disputes or any matter likely to be reviewed by the ATO or tested in litigation. Advisers modelling a practice under different scenarios — a lateral partner departure, a merger, a succession pathway tested against a sale — are better served by the Valuation Range & Scenario Review (from $12,995 + GST, 30–45 business days). Rush turnaround is available at +30% of the base fee, subject to capacity.
The supportable answer
A law firm is worth a supportable range, not a percentage of fees quoted in a corridor conversation. The honest starting questions are: what would it cost to replace every working principal at a market salary, how much of the WIP and debtor book will actually convert to cash under new ownership, and how much of the client base is following a person rather than the firm. Our reports conclude at the most supportable position within that range, with the earnings normalisation, the WIP and lock-up treatment, and the personal-versus-institutional goodwill analysis documented — senior-reviewer signed under an independence statement, working file retained ten years, fees fixed at engagement and never contingent on the outcome. Where a party wants a number that suits the negotiation rather than the position the evidence defends, we will say so and decline the engagement on those terms.