Build REG study around three linked skills: (1) tracking shareholder and partner basis with the correct ordering rules, (2) matching the tax result to the entity's federal classification, and (3) separating realized gain, recognized gain, and ordinary-versus-capital character. Work multi-year fact patterns rather than isolated definitions, and score yourself against a written rubric so you can see exactly which rule you skipped.
Basis: The Concept That Connects REG's Tax Areas
Treat basis as a running ledger, not a one-time number. Every contribution, income allocation, distribution, deduction, and loss either increases or decreases it, and the order of those steps changes the final taxable result.
Start by naming the distinct basis regimes so they do not blur: a partner's outside basis in the partnership interest, a partnership's inside basis in its assets, an S corporation shareholder's stock basis, and the separate debt basis a shareholder builds only by lending personally to the corporation. Each has its own adjustment list. For example, entity-level liabilities generally increase a partner's outside basis, while they do not increase S corporation stock basis.
Then learn the ordering rules, because they decide outcomes. For S corporations, stock basis adjustments follow a sequence: additions for allocated income and contributions, then reductions for distributions, then deductions and losses limited to the basis remaining at that point. Because distributions step down before deductions and losses, the same facts can produce a deductible loss or a suspended one depending on where the steps land. Practice by writing the order before any arithmetic.
- Outside basis: the owner's investment measure in the entity interest.
- Inside basis: the entity's tax basis in its own assets.
- Stock basis vs. debt basis: separate ledgers for an S shareholder; corporate-level debt does not count.
- At-risk and passive activity limits: separate loss restrictions layered on top of basis.
C Corporation, S Corporation, or Partnership: Classification Changes the Computation
Before computing anything, decide how the entity is classified for federal tax purposes, because classification controls whether income is taxed at the entity level, flows to owners, and how distributions are treated.
Compare the three default models side by side. A C corporation is a separate taxable taxpayer; its distributions to shareholders are treated as dividends to the extent of earnings and profits. An S corporation generally passes income through to shareholders, but its distributions are returns of capital against stock basis, and built-in gains can carry special treatment. A partnership passes income through and adds owner shares of entity liabilities to outside basis.
Use classification as a first diagnostic step in every tax question: identify the entity type, then pick the matching rule set before touching numbers. Trace this example: the same $40,000 distribution produces a dividend analysis in a C corporation, a basis reduction with possible gain in an S corporation, and a largely tax-free reduction of outside basis in a partnership. Misidentifying the entity means applying a complete set of the wrong rules.
| Feature | C corporation | S corporation | Partnership |
|---|---|---|---|
| Default federal tax treatment | Separate taxable entity | Pass-through to shareholders | Pass-through to partners |
| Owner's basis ledger | Stock basis only | Stock basis plus separate debt basis | Outside basis, adjusted for share of liabilities |
| Distribution result | Dividend to the extent of earnings and profits, then return of capital | Return of stock basis; gain once basis is exhausted | Generally tax-free reduction of outside basis |
| Entity-level income tax | Yes | Generally no, with special built-in gain considerations | No |
Property Transactions: Realized Gain, Recognized Gain, and Character
Separate three decisions: how much gain is realized (amount realized minus adjusted basis), how much is recognized (realized amount modified by rules), and what character the recognized gain carries (ordinary or capital).
Compute in a fixed order. Amount realized equals what you receive, including liabilities the buyer assumes, minus selling costs. Adjusted basis equals original basis plus capital improvements minus depreciation allowed or allowable. Realized gain is the difference. Only then apply recognition rules, such as whether a like-kind exchange or an involuntary conversion defers part of the gain, and whether depreciation recapture converts a portion to ordinary income.
Character is easy to leave undecided because the computation appears complete once the realized gain is calculated, yet it changes the final answer completely. Depreciation recapture provisions apply to personal property held in a trade or business, pulling gain attributable to prior depreciation back into ordinary income even though the asset itself is a business asset, not an investment. Trace this example: a business machine sold at a gain can produce entirely ordinary income with zero capital gain. State the character rule before you calculate.
Worked Scenario: An S Corporation Distribution That Looks Tax-Free but Isn't
A shareholder receives $35,000 from an S corporation with $10,000 stock basis and a $20,000 personal loan to the corporation. Treating the whole amount as tax-free is the mistake; distributions touch stock basis only, so a gain results.
The computation: distributions from an S corporation reduce stock basis only. Debt basis never absorbs distributions; it matters for absorbing losses and for the treatment of loan repayments. With $10,000 of stock basis, the first $10,000 received is a tax-free return of capital, and the remaining $25,000 is treated as gain from the sale or exchange of the stock, generally capital in character under the Section 1368(b)(2) framework.
The plausible mistake: the shareholder recalls that S corporation distributions are generally not income, sees the $20,000 personal loan as extra 'basis,' and reports the full $35,000 as tax-free. That conclusion fails twice: debt basis is simply not a distribution ledger, and basis must be verified before any tax-free conclusion. It matters because the same cash can be a return of capital or a capital gain depending on which ledger was available.
Worked Scenario: A Machine Sale Where Character, Not Amount, Is the Trap
A business machine bought for $80,000 with $50,000 of depreciation taken is sold for $60,000. Reporting the $30,000 gain entirely as capital gain is the mistake; the recapture rule makes it ordinary.
The computation: amount realized $60,000 minus adjusted basis of $30,000 ($80,000 cost minus $50,000 depreciation) equals $30,000 realized and fully recognized. The plausible mistake: seeing a sale of equipment and concluding the entire gain is Section 1231 capital-type gain, which would receive favorable treatment against any capital losses the taxpayer has.
The better decision: apply the depreciation recapture rule for depreciable personal property before characterizing anything. The recapture amount is the lesser of depreciation taken or realized gain; here that is $50,000 versus $30,000, so the full $30,000 gain is reclassified as ordinary income. It matters because character drives how the gain interacts with other items on the return, and a taxpayer with capital losses would see no offsetting benefit. Extend the pattern: had the gain exceeded accumulated depreciation, only the depreciation-covered portion would be ordinary.
Tracing Business Law Through a Fact Pattern, Not a Definition List
Practice business law by tracing authority, formation, and liability steps inside a fact pattern rather than memorizing isolated definitions of each doctrine.
Take agency as the model. Trace the chain: does an agency relationship exist, what scope of authority did the principal grant (express, implied, or apparent), did the agent act within it, and was the agent's conduct ratified? Each link changes who is bound. In one pattern, an employee with implied authority to order supplies binds the principal; in a nearly identical pattern, a terminated agent who retains a catalog binds the principal only under apparent authority, because the third party reasonably relied on appearances.
Apply the same tracing habit to secured transactions and suretyship. For a security interest, follow the sequence: attachment (value given, debtor rights, security agreement), then perfection (typically filing), then priority against competing claims. For suretyship, identify the type of surety, any defenses, and whether the creditor's actions discharged the surety. The exercise: write each fact pattern as a numbered chain of legal tests, and check whether your conclusion cites the specific link where the pattern succeeded or failed.
- Self-check rubric for a business law pattern: (1) named the doctrine, (2) listed its required elements, (3) matched each fact to an element, (4) identified the dispositive link, (5) stated the liability result.
- Score 5 of 5 before moving on; a missing element match is the observation to fix, not the final answer.
Tax Procedure and Preparer Ethics: Rules With Dates and Duties
This area consists of precise rules: return preparation standards, penalties, the taxpayer's and preparer's filing obligations, and the time periods that limit assessment and refund claims.
Distinguish the limitation periods as separate concepts, not interchangeable dates. The general assessment limitation runs three years from filing; a substantial omission of gross income extends it; a fraudulent or unfiled return has no limit. Refund claims run on their own separate clock. Similarly, distinguish preparer penalty triggers: unreasonable positions with no substantial authority differ from willful or reckless conduct, and the knowledge standard depends on what the preparer actually knew from the client's information.
Layer in professional responsibility: a preparer may rely in good faith on client information but must make reasonable inquiries when information appears incorrect or incomplete. The practical exercise: build one timeline sheet pairing each trigger with its period and its consequence, then quiz yourself by trigger only. Readiness checks for this section: you can state which party a penalty attaches to, which events suspend or extend a limitation period, and how a conflict of interest under professional standards is identified and resolved.
References and further reading
Use these references to explore the concepts and check the latest information from the relevant organizations.