Prop Account LLC: Formation, TTS, and MTM Election

A prop account LLC is a limited liability company you form to trade your own capital through a business entity instead of a personal brokerage account. The structure gives you liability protection and a clean framework for business expenses, but the tax advantages people form these entities for, including business expense deductions and the Section 475(f) mark-to-market election, only exist if you also qualify for Trader Tax Status and file the right elections on time. Get the entity without the elections and you have an expensive shell that is taxed exactly like your old personal account.

What the Entity Actually Buys You

“Proprietary” in this context just means you are trading your own money. The LLC becomes the legal owner of the brokerage account, the trading equipment, and the business expenses that come with the activity. That ownership gives you a liability shield and a professional framework for recordkeeping.

What it does not do, on its own, is change your taxes. An LLC that holds a brokerage account but does not meet the IRS definition of a trade or business is taxed like any other investment account. The real benefits come from three pieces working together: the LLC itself, Trader Tax Status qualifying the activity as a business, and specific tax elections changing how gains, losses, and expenses are treated.

Forming the LLC

File Articles of Organization with the Secretary of State in your home state. Filing in your home state is almost always the practical choice, since registering a foreign entity adds cost and paperwork without changing your tax outcome. Filing fees in most states fall between $50 and $150.

Draft an Operating Agreement even if you are the only member. The agreement defines capital contributions, management authority, and how profits and losses are allocated. Courts look at this document when deciding whether the LLC is genuinely separate from you personally, and a missing or sloppy agreement weakens the liability shield you formed the entity to get.

Once the state filing clears, apply for an Employer Identification Number from the IRS. The IRS requires the state entity to exist before issuing an EIN, so you cannot work ahead on this.¹ You will need the EIN to open a business bank account and to make tax elections. Open the account, fund it with your capital contribution, and route every trading-related transaction through it. Mixing personal and business funds is the fastest way to lose liability protection.

Many states also charge annual reports or franchise taxes to keep the LLC in good standing. These range from nothing in some states to $800 or more in others. A missed annual filing can lead to administrative dissolution, so put the renewal date on a calendar the day you form.

Qualifying for Trader Tax Status

Trader Tax Status is not a box you check. It is a factual determination the IRS makes based on how you actually trade. Without it, your LLC is treated as holding investments, and the business expense deductions and mark-to-market election are off the table.

The IRS requires three conditions: you must seek to profit from daily market price movements rather than from dividends or long-term appreciation, your trading activity must be substantial, and you must carry it on with continuity and regularity. In practice the IRS and tax courts look at four factors: typical holding periods, the frequency and dollar amount of trades, how much income the trading produces relative to your livelihood, and the time you devote to the activity.²

There is no bright-line test. Some practitioners cite benchmarks like 720 or more trades per year with average holding periods under 31 days, but the IRS has never published those numbers. Tax court decisions consistently apply a facts-and-circumstances analysis, and extended stretches with no trading tend to defeat the claim even when raw trade counts look substantial. Patterns that consistently hold up: trading nearly every market day, holding positions for days rather than months, spending several hours daily on research and execution, and generating enough volume that the activity looks like a full-time occupation. Significant outside employment income and sporadic trading make you an investor in the IRS’s eyes regardless of the LLC.

What TTS Changes

A qualified trader deducts ordinary and necessary business expenses directly against income on Schedule C.² These include trading platform subscriptions, real-time data feeds, computer equipment, professional tax preparation, and a portion of home office expenses calculated on Form 8829.³ Equipment can be expensed immediately under Section 179, and off-the-shelf trading software qualifies.⁴

An investor gets none of this. Investment-related expenses like advisory fees and subscriptions fall under miscellaneous itemized deductions, which the Tax Cuts and Jobs Act suspended starting in 2018 and which the One Big Beautiful Bill Act permanently eliminated beginning in 2026. Investors cannot deduct these expenses at all.

Documentation

If the IRS audits your TTS claim, the burden of proof is on you. Keep a daily trading log that records your start and stop times, the number of trades executed, your research activities, and the strategy behind your positions. Brokerage statements show the trades themselves, but only your own records show the time and effort behind them. Traders who lose in tax court almost always lose on documentation, not on trading volume.

The Mark-to-Market Election

The Section 475(f) mark-to-market election is the single most valuable tax tool a qualified trader has, and it is only available with TTS. It changes how the IRS treats your gains and losses in three ways that matter.

Without MTM, trading losses are capital losses. You can deduct them only against capital gains, plus up to $3,000 per year against ordinary income, with the rest carried forward indefinitely.⁵ An $80,000 loss with no capital gains would take over 25 years to fully deduct. With MTM, net trading losses become ordinary business losses with no annual cap, so that same $80,000 offsets your full ordinary income in the year it occurs, including a spouse’s wages on a joint return.²

The election also exempts you from wash sale rules. For a trader cycling the same securities dozens of times a day, wash sale adjustments can create phantom taxable gains that bear no relation to actual economic results, and the exemption removes that distortion. MTM also simplifies year-end reporting, since all positions held on December 31 are treated as sold at fair market value on the last business day of the year.

The Trade-Off

Every MTM gain is taxed as ordinary income regardless of how long you held the position. You give up the preferential long-term capital gains rate, which tops out at 20% for most high earners. If any part of your strategy involves holding positions longer than a year, MTM can cost more than it saves. The election fits traders who rarely hold positions beyond a few days, where long-term capital gains treatment was never in play.

The election is also effectively permanent. Revocation requires IRS permission and is rarely granted.

Election Deadlines

The deadlines here are unforgiving, and this is where most traders who want MTM run into trouble.

If you were required to file a return for the prior year, you must file a statement electing Section 475(f) by the original due date, without extensions, of that prior-year return. To have MTM for 2027, the statement must be attached to your 2026 return (or to a timely extension request) filed by April 15, 2027. The statement must identify the election under Section 475(f), the first tax year it applies to, and the specific trade or business.²

A new taxpayer who was not required to file a return for the prior year gets a different window. You must place the election statement in your books and records no later than two months and 15 days after the first day of the election year, then attach a copy to your return for that year.² This is a real advantage of forming a new LLC: a brand-new entity that begins trading on January 1 has until March 17 to make the election for that same year, instead of waiting an entire tax year.

Choosing a Tax Classification

An LLC is a “check-the-box” entity. The default classification depends on member count, but you can elect something different.

A single-member LLC defaults to a disregarded entity, taxed like a sole proprietorship, with income and expenses flowing to Schedule C.⁶ A multi-member LLC defaults to partnership taxation on Form 1065 with K-1s to each member.⁷ For many TTS traders, the default single-member structure is enough: business expenses on Schedule C, gains and losses on Schedule D, or Form 4797 with the MTM election. Simple, low compliance cost.

S-Corporation Election

An LLC can elect S-Corporation taxation by filing Form 2553. A new LLC must file within 75 days of its formation date for the election to apply to its first tax year. The S-Corp is still a pass-through, but it changes how employment taxes work: the owner-employee splits compensation into a reasonable salary subject to payroll taxes and distributions that avoid them.⁸ The self-employment tax rate is 15.3%, covering 12.4% for Social Security on earnings up to $184,500 in 2026, plus 2.9% for Medicare on all earnings.⁹

For traders, there is a complication. Without MTM, trading gains are capital gains and generally fall outside self-employment tax to begin with. With MTM, gains are ordinary income, and whether that income is subject to SE tax is a genuinely unsettled question among tax practitioners. Some argue MTM gains from a trade or business are net earnings from self-employment; others hold that the character of trading gains exempts them regardless. The practical consequence is that S-Corp savings are not automatic for every trader, and modeling your specific situation with a specialist is the only way to know whether the election adds value.

If you do elect S-Corp status, the salary you pay yourself must be reasonable. The IRS weighs your training and experience, time devoted to the business, pay for comparable roles, and the relationship between salary and distributions.¹⁰ Setting the salary artificially low to maximize distributions is the exact pattern the IRS challenges.

C-Corporation Election

An LLC can elect C-Corporation taxation by filing Form 8832. C-Corp profits face a flat 21% federal corporate income tax, and distributions to you are then taxed again as dividends.⁷ For most prop traders the pass-through structure makes more sense. A C-Corp election is worth considering only if you plan to retain significant earnings in the entity at the 21% rate or want access to fringe benefits available only to corporate employees.

Professional Market Data Fees

One cost that catches new trading LLCs off guard is the reclassification of market data subscriptions. Exchanges like CME Group classify subscribers as either professional or non-professional, and trading through a business entity almost always triggers professional status.

The price difference is large. CME Group’s January 2026 fee schedule charges non-professional subscribers as little as $4.65 per month for a bundled top-of-book package across all four exchanges. Professional subscribers pay $134.50 per month for a single display device with real-time data, and E-Mini data packages for professionals run from $42.25 to $73.00 per exchange per month.¹¹ Similar reclassifications apply across NYSE, Nasdaq, and other exchanges. These fees are deductible business expenses under TTS, but the increase hits as soon as your brokerage account is registered to the LLC, so budget for it before forming.

Foreign Account Reporting

If your trading LLC holds capital in foreign brokerage accounts or trades through a foreign platform, two separate reporting rules may apply. Under FATCA, individuals must file Form 8938 when total foreign financial assets exceed $50,000 on the last day of the tax year or $75,000 at any point during the year for unmarried filers. The thresholds double for married couples filing jointly.¹²

Separately, FinCEN Form 114 (the FBAR) is required for any U.S. person with a financial interest in or signature authority over foreign accounts exceeding $10,000 in aggregate at any point during the year. Filing Form 8938 does not satisfy the FBAR requirement; both must be filed independently.¹² FBAR penalties are steep and can reach $10,000 or more per violation even for non-willful failures.

Sequence and Timing

Several deadlines are tied to formation and cannot be extended, so the order matters.

File Articles of Organization. This starts the clock on everything else.
Draft the Operating Agreement before any capital is contributed or trades placed.
Apply for an EIN once state formation is confirmed. The online process takes minutes.¹³
Open a business bank account and fund it with the capital you intend to trade.
Open the brokerage account in the LLC’s name using the EIN, Articles of Organization, and Operating Agreement.
File Form 2553 within 75 days if electing S-Corp status. Miss this and you wait until the next tax year.
Place the MTM election statement in your books and records within two months and 15 days of the first day of the election year. For a new entity, this is the only chance to elect MTM for the first trading year.²
Start trading and start logging activity on day one.

Many traders form the LLC in late December so the entity exists on January 1 of the new tax year, maximizing the window for both the MTM election and the S-Corp filing. Forming mid-year leaves the same deadlines in place but shortens the trading record for that first year, which can weaken a TTS claim because you have fewer months to demonstrate substantiality and continuity. Working with a CPA or tax attorney who specializes in trader taxation before you file the first form is the most cost-effective step in the whole process.

1
Internal Revenue Service. Get an Employer Identification Number
2
Internal Revenue Service. Topic No. 429, Traders in Securities
3
Internal Revenue Service. Instructions for Form 8829
4
Internal Revenue Service. Publication 946, How To Depreciate Property
5
Office of the Law Revision Counsel. 26 U.S. Code 1211 – Limitation on Capital Losses
6
Internal Revenue Service. Entities 3
7
Internal Revenue Service. LLC Filing as a Corporation or Partnership
8
Internal Revenue Service. S Corporations
9
Internal Revenue Service. Self-Employment Tax (Social Security and Medicare Taxes)
10
Internal Revenue Service. S Corporation Employees, Shareholders and Corporate Officers
11
CME Group. January 2026 Market Data Fee List
12
Internal Revenue Service. Summary of FATCA Reporting for U.S. Taxpayers
13
Internal Revenue Service. About the Employer Identification Number