How much is a typical Big Law partnership capital contribution?

AmLaw 10–50 firms typically require $400K–$800K. AmLaw 51–200 firms range $200K–$500K. Some firms stage the contribution over 2–3 years; others require full payment at admission. In most structures, 60–90% can be financed via a firm promissory note.

Is the partnership capital contribution tax deductible?

No — the capital contribution itself is not deductible. You are acquiring a partnership interest (a capital asset). Interest paid on a loan used to fund the buy-in may be deductible under IRC §163(d) as investment interest expense, but only to the extent of net investment income. This is frequently misunderstood.

What happens to my capital account if I leave the firm?

Under IRC §736(b), liquidating payments for your capital account interest (tangible assets) are treated as capital gain or ordinary income depending on the firm's asset composition. The timeline for return varies widely — some firms pay immediately, others over 3–10 years. The partnership agreement controls this, not defaults rules.

How much more will I pay in self-employment tax as an equity partner vs. associate?

As a W-2 associate, you paid 7.65% FICA (employee side) on wages up to the Social Security wage base ($184,500 in 2026), plus 1.45% Medicare on all wages. As a K-1 equity partner, you owe 15.3% SE tax on 92.35% of net earnings up to $184,500, plus 2.9% above that — but you get to deduct 50% of SE tax, saving roughly 18–19% of the SE tax at a 37% marginal rate. The real shock isn't the total amount: it's the timing — no withholding means you must make four quarterly estimated payments.

Is equity partner income really higher than staying senior associate or of-counsel?

On a 10-year horizon, equity partnership usually produces significantly more after-tax income at AmLaw 50 and large-firm tiers, where first-year partner PEP distributions typically exceed senior associate comp by $300K–$600K/year. The math is tighter at smaller firms or if your book of business is firm-dependent. Run the model before committing, because the first 12–18 months often show lower net income than your final associate year.

When does the capital contribution pay back?

On a cash-on-cash basis: at a $400K contribution and $900K first-year K-1 distribution, after SE tax (~$45K), loan servicing (~$65K/year), and income tax (~$350K), year-1 net take-home is roughly $440K — higher than a senior associate's ~$300K after-tax. The capital contribution 'pays back' in the sense that the income premium typically exceeds the financing cost within 2–3 years. But the capital account remains illiquid until you leave.

Big Law Partnership Buy-In: The Real Financial Decision

Your firm just voted you in. The offer letter mentions a "capital contribution of $450,000, payable per firm procedures." The instinct is to focus on that number — how to fund it, whether to use the firm loan. But the capital contribution is only one of three simultaneous financial shocks in year one of equity partnership. Missing the other two is how new partners end up with a surprise $200K April tax bill.

Capital contribution amounts by firm tier

Contributions vary significantly by firm size and market position:

Firm tier	Typical range	Firm-loan availability	Interest on capital (firm pays you)
AmLaw 10–50	$400K–$800K	60–90% financed	3–6%
AmLaw 51–200	$200K–$500K	50–80% financed	2–5%
Mid-size / boutique	$75K–$250K	Varies widely	1–4%

The firm pays you a low interest rate on your capital account balance — think 3–6%. That is not a good investment return. The return on your buy-in comes from the profit distributions you receive as an equity partner, not the capital interest itself. The capital contribution is the price of admission to the distribution stream.

The capital itself is not deductible. You are acquiring a partnership interest — a capital asset. Interest paid on a loan to fund the buy-in may be deductible as investment interest expense under IRC §163(d), but only to the extent of net investment income. A common first-year partner mistake is assuming the $400K is a deductible business expense.

The three year-one financial shocks that hit simultaneously

Most new partners focus on funding the capital contribution. What catches them off guard is that two other large costs land at the same time:

Cash out: the capital contribution. $200K–$800K due at or near the partnership effective date. Most is financed via a firm promissory note, but you still need 10–40% in liquid cash at closing.
SE tax shock: W-2 to K-1 transition. As an associate, FICA taxes (7.65% of wages, employee side) were withheld automatically. As a K-1 equity partner, you owe self-employment tax — effectively both the employer and employee portions — on 92.35% of your net earnings. The SE deduction partially offsets this, but the absolute dollar amount is far larger than your prior FICA bill.
Withholding disappears: quarterly estimated taxes required. No W-2, no withholding. Your entire federal, state, and SE tax obligation for the year must be paid in four quarterly installments (April 15, June 16, September 15, January 15 for 2026). First-year partners who don't set this up correctly often face a large underpayment penalty on top of the April bill.

SE tax year-one calculator

This calculator estimates your SE tax as a new equity partner and compares it to the FICA you paid as a W-2 associate. It shows your quarterly estimated payment obligation — the number you need to put in your calendar starting now.

The real ROI math on your capital

The right way to think about partnership economics is: what is my after-tax, after-financing return on the capital I'm putting in?

Using round numbers at an AmLaw 100 firm:

Capital contribution: $450,000 (80% financed via firm loan at 7.5%, 7-year term = ~$67K/year servicing)
Your equity contribution: $90,000 out of pocket
First-year K-1 distribution: $900,000
SE tax (after 50% deduction): approximately $45,000
Income tax at 45% combined: ~$380,000
Loan servicing: ~$67,000
Net take-home: ~$408,000
vs. senior associate after-tax at $450K gross: ~$270,000

The income premium over staying as a senior associate is roughly $138,000 in year one — and it grows substantially in subsequent years as comp scales. Even accounting for the capital opportunity cost (interest foregone on $90K of liquid savings = ~$4,500/year), the return on equity is exceptional.

The case against is not usually financial — it's the job. Partners originate, manage, sit on committees, and carry firm responsibility. If what you loved as an associate was the work itself, the financial premium may not compensate for the role change.

W-2 to K-1: what changes on your tax return

The tax transition is the biggest source of first-year surprises. Four things change immediately:

1. Self-employment tax replaces FICA

As a W-2 associate, your employer withheld 7.65% FICA (6.2% Social Security up to $184,500 SS wage base¹ + 1.45% Medicare) from your paycheck. As an equity partner with K-1 income, you pay SE tax on Schedule SE: 15.3% of 92.35% of net earnings up to the SS wage base, plus 2.9% above that. You deduct 50% of the SE tax on Schedule 1. At a $900K distribution, SE tax (before the deduction) is roughly $48K–$50K.

2. §199A SSTB phase-out

Law firms are Specified Service Trades or Businesses (SSTBs) under §199A. The QBI deduction phases out for equity partners with taxable income roughly between $200K and $275K (single) and $400K to $550K (MFJ) under 2026 thresholds. Most Big Law equity partners are fully phased out from day one. See our §199A guide for law firm partners for the exact math and planning strategies.

3. Quarterly estimated payments — required

You must make quarterly estimated payments covering federal income tax + SE tax to avoid the IRC §6654 underpayment penalty. The safe harbors: pay 90% of current-year tax, or 110% of prior-year tax (if prior-year AGI > $150K, which it almost certainly is). Most first-year partners use the 110% prior-year safe harbor in Q1–Q3, then true-up in Q4 once actual distributions are known. Due dates in 2026: April 15, June 16, September 15, January 15, 2027.

4. Benefit cliff

Your W-2 employer-sponsored benefits end: the employer's 401(k) match structure may change, group health insurance ends (you need to arrange partner coverage), and firm-paid disability coverage may be limited. Coordination of benefits on your transition date matters — particularly disability insurance FPO riders (you must apply before your W-2 status ends). See the pre-partnership financial checklist.

Compensation model and what it means for your distributions

The comp model you're entering determines the range and variability of your distributions — which changes the financial case for partnership entirely.

Pure lockstep (Cravath, Sullivan, Cleary): distributions scale by seniority. Predictable, and your P1 distribution is a known number. Risk is low; ceiling is also lower than eat-what-you-kill for rainmakers.
Modified lockstep (most AmLaw 50): base seniority formula adjusted for origination and book size. More variable. Know your origination credit formula before signing.
Eat-what-you-kill (boutiques and some practice groups): distributions tied heavily to your origination. High variance. The capital ROI math is very sensitive to portability assumptions — if 30–50% of your book stays with the firm on departure, the numbers change significantly.

Before you accept equity partnership, know which model applies to you and run the 5-year scenario: what does your take-home look like if your origination credit comes in at 70% of expectation? At 50%? Model the downside, not just the upside. See the lockstep vs. EWYK calculator for year-by-year after-tax comparison.

Capital account mechanics when you leave

Your partnership capital account is an illiquid asset. When you leave — whether to lateral, go in-house, retire, or convert to of counsel — the firm returns your capital per the partnership agreement's schedule. The tax treatment depends on the composition of firm assets:

IRC §736(b) payments: return of your capital account interest in tangible assets (receivables, WIP). Taxed as ordinary income (unrealized receivables) or capital gain (goodwill, if the agreement provides for it in service partnerships).
IRC §736(a) payments: payments for your share of unrealized receivables and "goodwill" not fixed by agreement in service partnerships. Taxed as ordinary income in year received.
Timeline: ranges from immediate (some firms) to 3–10 years of annual installments. Holdbacks tied to firm profitability are common. Clawback provisions can apply if you depart with your book within a specified window.

The illiquidity of the capital account is a real risk, especially at firms showing financial stress. At departure-year income stacking — capital return + NQDC distributions + final distributions — can create a massive one-year tax event. See partner retirement tax mechanics for a full breakdown.

Funding the buy-in: your options

The most common structures, in order of frequency:

Firm promissory note (most common): 60–90% of contribution financed by the firm at 7–9% over 5–10 years. Principal and interest serviced out of monthly draws. Simple, no outside lender approval required.
Commercial bank loan / securities-backed line: SBLOC against an investment portfolio. Lower rate than the firm note (often SOFR + 1–2%), but requires liquid brokerage assets of 1.5–2× the loan amount.
Portfolio margin: similar to SBLOC but more leverage. Rate and margin-call risk higher.
Savings: paying cash avoids interest cost but depletes the liquidity buffer needed for quarterly tax payments in year one — a trade-off worth modeling.

See the full analysis in funding your partnership capital contribution, including the IRC §163(d) interest deductibility mechanics.

Equity vs. non-equity vs. in-house: the financial comparison

Not all partners face a binary equity/leave choice. Many firms have a non-equity (income) partner tier. The financial comparison:

Track	Year-1 income (typical AmLaw 100)	Capital required	Tax complexity	Upside
Equity partner	$700K–$1.5M+ K-1	$300K–$700K	SE tax, K-1, quarterly estimates	Uncapped via origination
Non-equity partner	$350K–$700K W-2 or guaranteed payment	None or $50K–$150K	W-2 or limited K-1	Limited; tied to firm's willingness to promote
In-house (GC/VP Legal)	$400K–$900K total comp (base + RSU)	None	W-2 + RSU vesting	Equity upside if pre-IPO; lower ceiling at mature cos.

On a pure 10-year NPV basis, equity partnership at large firms wins handily — if your origination credit holds. The in-house path is financially rational when the company's equity value creates meaningful upside and when the lifestyle trade-off (fewer billable hours, more operational work) is worth it. See partner to in-house transition guide and equity partner decision framework for deeper analysis.

Year-one financial checklist for new equity partners

90 days before start: apply for individual disability insurance with FPO rider (before W-2 status ends and firm group coverage lapses).
30 days before start: make §409A initial NQDC deferral election (must be made before becoming a partner; can't retroactively elect). See NQDC guide.
Day 1: set up quarterly estimated tax calendar. Wire first payment if Q1 deadline has passed.
Month 1: open solo 401(k) or confirm firm's partner 401(k) plan structure; coordinate health insurance transition; update disability and life insurance beneficiaries.
Month 2–3: establish tax reserve account — deposit 40–45% of each draw into a separate savings account designated for taxes.
Before December 15: make NQDC election for next year's distributions (only annual window for §409A elections).

Sources

SSA, Contribution and Benefit Base 2026 — $184,500.
IRS, Topic 554: Self-Employment Tax — SE tax rates, Schedule SE, and 50% deduction.
IRC §736 — Payments to a Retiring Partner or a Deceased Partner's Successor in Interest (Cornell Law School LII, 26 U.S.C. § 736).
IRS, Rev. Proc. 2025-32 — 2026 inflation adjustments including §199A SSTB phase-out thresholds and tax bracket amounts.
IRC §163(d) — Limitation on Investment Interest (investment interest deductibility for capital contribution loan interest).

Tax values verified as of August 2026. SE tax rate, SS wage base, and §199A thresholds subject to annual adjustment.

Get your partnership offer modeled

A specialist advisor will run the 10-year NPV on your specific firm's capital structure, comp model, and your tax situation — including the year-one shock math. No obligation.