Federally, assets held more than one year produce long-term capital gains taxed on a preferential schedule; one year or less is short-term and taxed as ordinary income. California makes no such distinction and taxes all capital gains as ordinary income. A separate federal net investment income tax can apply above certain thresholds. The levers investors control are holding period, loss harvesting, timing across tax years, lot selection and charitable or estate mechanics — but the tax cost of a sale is bounded and knowable, while concentration risk is not.
The federal distinction: short-term versus long-term
Federal law splits capital gains by holding period. An asset held more than one year before sale produces a long-term capital gain, taxed on a preferential rate schedule. An asset held one year or less produces a short-term capital gain, taxed as ordinary income at the taxpayer's marginal rate. The holding period generally starts the day after acquisition and runs through the day of sale.
That distinction is structural and durable — long-term gains run through a 0%, 15% and 20% schedule, and the income thresholds separating those brackets are indexed and move every year, but the one-year line has been a fixture of the code for decades. It is the reason "held just under a year" shows up so often as a costly accident in taxable accounts.
California adds no second distinction
On the California return, that carefully-observed one-year line does nothing. California taxes capital gains as ordinary income — long and short alike — at the taxpayer's marginal state rate, with California's top marginal rate among the highest of any state — 13.3%, being the 12.3% top bracket plus the 1% Mental Health Services Tax on income above $1 million. There is no California long-term rate to qualify for.
So a California investor selling an appreciated position faces two separate calculations that behave differently: a federal bill that may be materially reduced by patience, and a state bill that is not reduced by patience at all. Holding past one year still helps — it just helps on one of the two returns.
The net investment income tax, conceptually
Above certain modified-adjusted-gross-income thresholds, a separate federal surtax — the net investment income tax — applies to net investment income, which includes capital gains, dividends, taxable interest, rents and royalties. It is not part of the capital gains rate schedule; it sits on top of it, which is why the "all-in" federal cost of a large realisation can exceed the headline long-term rate. The rate and the income thresholds are set by statute at 3.8%, on modified adjusted gross income above $200,000 single, $250,000 married filing jointly and $125,000 married filing separately (IRC § 1411), and the thresholds are notably not indexed the way many other figures are.
California has no state analogue to this surtax; it simply taxes the gain as ordinary income. The planning relevance is that a single large sale can push a household across a threshold it was comfortably under, and the crossing is often invisible until the return is prepared — a reason to run a projection with a CPA before a large realisation, not after.
| Question | Federal | California |
|---|---|---|
| Does holding period change the rate? | Yes — over one year is long-term | No |
| Preferential rate for long-term gains? | Yes, separate schedule | No — ordinary income |
| Qualified dividends preferential? | Yes | No |
| Surtax on investment income? | Net investment income tax above thresholds | No direct analogue |
| Capital losses offset gains? | Yes | Yes, generally conforming |
| Excess loss against ordinary income | Up to $3,000 per year; remainder carries forward | Generally conforms; confirm with your CPA |
The levers that actually exist
Once the structure is clear, the list of things an investor can genuinely control is short — which is itself useful information.
- Holding period. Crossing the one-year line changes federal treatment. When a position is near it and there is no investment reason to sell now, waiting is often the cheapest decision available. When there is an investment reason, the reason usually wins.
- Loss harvesting. Realised losses offset realised gains, and up to $3,000 of net loss can offset ordinary income each year, with the remainder carrying forward indefinitely. This is the most reliably useful lever in a volatile year — mechanics and limits are in the tax-loss harvesting guide.
- Timing across tax years. Splitting a large realisation across two years, or realising into a year with unusually low income (a sabbatical, a business loss, the gap between retirement and the start of Social Security), can change the bracket the gain lands in — see the Social Security timing guide.
- Lot selection. Specifying which tax lots are sold, rather than accepting a default, can change the gain realised on an identical trade. This must be done at the time of sale and properly recorded by the custodian.
- Charitable and estate mechanics. Gifting appreciated securities, or the treatment of assets at death, can change the basis picture entirely — see qualified charitable distributions and estate basics for Californians. These are CPA and estate-attorney territory.
Why the old warning still applies
"Don't let the tax tail wag the investment dog" survives because the failure mode it describes is so common and so expensive. A household holds a single stock at a low basis for a decade because the tax bill feels intolerable, and the concentration risk — not the tax — is what eventually costs them. Another defers a rebalance repeatedly and drifts into an allocation nobody chose.
The asymmetry is worth stating plainly: the tax cost of selling is calculable in advance and usually a fraction of the position. The cost of an undiversified portfolio meeting a bad outcome is neither calculable nor bounded. Tax should inform sequencing, lot selection and timing rather than being the reason a portfolio stays wrong.
Where the two genuinely conflict, the useful move is to price the trade-off rather than avoid it — model the after-tax cost of the change alongside the risk being carried, and decide with both numbers visible. That is the work our investment management and planning engagements do with clients and their CPAs. Aduna Capital does not provide tax or legal advice. Nothing here is a recommendation for your situation — consult your CPA or tax attorney before acting.
Common questions
If California ignores the holding period, is there any point waiting a year?
Often yes — the federal side is usually the larger of the two bills, and the preferential long-term schedule applies there. California's treatment does not erase the federal benefit; it just means the benefit is smaller in total than a resident of a no-income-tax state would see. Whether waiting makes sense in a specific case depends on the position and the household's rates.
What happens to capital losses I cannot use this year?
Net capital losses first offset capital gains. Beyond that, up to $3,000 per year can offset ordinary income, and any remainder carries forward to future years indefinitely for federal purposes. California generally conforms to the offset structure — confirm the specifics of your carryforward with your CPA and at ftb.ca.gov.
Does the net investment income tax apply to everyone?
No — it applies only above statutory modified-AGI thresholds, and only to net investment income. Many households never encounter it; households with a large one-time realisation sometimes encounter it exactly once. The current rate and thresholds should be confirmed at irs.gov and with a CPA before a large sale.
Can I just hold everything until death and avoid capital gains?
Basis treatment at death is a real and significant part of the code, and it is a legitimate input to planning. It is also a strategy with obvious costs — decades of concentration risk, an illiquid plan, and rules that can change. It belongs in a conversation with an estate attorney and a CPA alongside the rest of the estate plan, not as a default.
Sources
- IRS, Topic No. 409, Capital Gains and Losses, irs.gov
- IRS, Publication 550, Investment Income and Expenses, irs.gov
- IRS, Questions and Answers on the Net Investment Income Tax, irs.gov
- California Franchise Tax Board, capital gains and personal income tax guidance, ftb.ca.gov
Planning a large sale?
We model the after-tax cost of a realisation alongside the risk of holding — and coordinate the timing with your CPA before the trade, not after.