What Is Basis?

Basis is the running total of what you've put into an investment, minus what you've taken out, adjusted for the income and losses the investment has generated along the way. The IRS uses that one number to answer three separate questions:

1. Can you deduct losses? Only up to your basis. A $100,000 loss with $1,000 of basis is a $1,000 deduction this year — the rest waits.

2. Are distributions tax-free? Only up to your basis. Pull out more than your basis and the excess is taxed as capital gain — even though it's your own company's cash.

3. How much gain do you report when you sell? Sale price minus basis equals taxable gain. A sloppy (or missing) basis number means an inflated tax bill.

Imagine your investment (S-Corp, Partnership, Building) is a bucket.

The bucket metaphor sounds simple, but it explains nearly every basis problem we see. Owners assume the bucket refills automatically because the business "is doing fine." It doesn't. The bucket only refills when you contribute money, lend money directly, or the business reports taxable profit on your K-1. Depreciation deductions, distributions, and losses all drain it — often faster than owners realize.

Here's how the math plays out over a few years for a typical S-Corp owner:

Worked example. You launch a consulting S-Corp with a $50,000 contribution. Year 1, the company earns $30,000 of profit (reported on your K-1, taxed to you whether or not you take the cash) and you take a $20,000 distribution. Your ending basis: $50,000 + $30,000 − $20,000 = $60,000. Year 2, the company invests heavily, reports a $75,000 loss, and you take no distributions. You can deduct $60,000 of that loss; the remaining $15,000 is suspended until your basis comes back above zero.

One more wrinkle worth knowing: the adjustments happen in a set order each year — income items first, then distributions, then losses. That ordering matters. In a year with both a distribution and a loss, the distribution soaks up basis before the loss does, which can suspend a loss you assumed was deductible.

S-Corps are notorious for basis issues. Why? Because bank loans do NOT give you basis in an S-Corp (unlike a Partnership).

Example:

• You start a business with $1,000.
• The business borrows $100,000 from a bank.
• The business buys $100,000 of equipment and uses Bonus Depreciation to write it all off.

The Trap: You have a $100,000 loss, but your basis is only $1,000. You can only deduct $1,000. The remaining $99,000 is "suspended" until you put more money in or make a profit.

Two details make this trap worse than it looks. First, personally guaranteeing the bank loan does not help — guarantees don't create basis for an S-Corp shareholder. Second, the common workaround of running the loan through yourself only works if it's done properly: you borrow personally, then lend the funds directly to the company under a documented note (a "back-to-back" loan). Sloppy versions — where the bank wires straight to the company and you just sign — have repeatedly failed when challenged.

This is also where basis collides with the other loss rules. Clearing the basis hurdle is only step one — the loss still has to survive the at-risk rules, the passive activity rules, and the excess business loss limits. Planning a big bonus depreciation year without checking all four gates is how owners end up with a six-figure deduction on paper and a near-zero deduction on the return.

Basis also determines if taking money out of your company is taxable.

Generally, taking a "distribution" (profit share) is tax-free because you've already paid tax on the profit.

However: If you take out more cash than you have basis, the IRS treats the excess as a capital gain. You effectively pay tax on your own cash withdrawal because you "overdrew" your tax equity account.

Worked example. Your basis is $40,000 after several loss years. The company has cash, so you distribute $90,000 to yourself. The first $40,000 comes out tax-free and zeroes your basis. The remaining $50,000 is a capital gain — at a 23.8% combined rate (20% long-term capital gain plus the 3.8% net investment income tax), that's roughly an $11,900 tax bill on money you thought was already yours. Nothing about the company changed; only the bucket ran dry.

This surprise almost always surfaces in March, when the return is being prepared and the distribution already happened. The fix is timing: check basis before year-end distributions, and if the bucket is low, either defer the distribution or restore basis first.

Every dollar of basis you can document is a dollar of sale proceeds you don't pay tax on. When you sell your interest, the gain is simply sale price minus basis.

Worked example. You sell your S-Corp stock for $250,000. With a documented basis of $60,000, you report a $190,000 long-term capital gain — roughly $45,220 of tax at a 23.8% combined rate. With no records, the IRS's default position can be that your basis is zero, making the entire $250,000 taxable — about $59,500. The difference, around $14,000, is the price of not keeping a schedule.

The IRS has tightened this up. S-Corp shareholders who claim losses, take distributions, receive loan repayments, or sell stock are generally required to attach Form 7203 to their personal return showing the basis computation. "I never tracked it" is no longer a workable answer — it's an audit flag.

If you've never tracked basis, it can be reconstructed: original contributions, every K-1 since inception, and the distribution history rebuild the schedule year by year. It's exactly the work we do in our owner basis management engagement — and the earlier it's done, the cheaper it is.