Best Tax Loss Harvesting Software for California Investors

A harvested loss is worth what your combined marginal rate says it is worth, and California adds up to 13.3% to that rate because it gives capital gains no preferential treatment at all. For a single Californian on $245,000, a long-term harvested loss is worth 28.1% against 18.8% for the same investor in Texas. Run that through the incremental harvesting yield Wealthfront published in its own whitepaper and the annual benefit moves from about 19 basis points of account value to about 28. That is the entire decision: it lifts Frec and Wealthfront at 0.09% from good to obvious, it makes Parametric's 23 bps tier defensible, and it still does not rescue a 0.40% product.

This is educational. We build index construction and backtesting software. We do not manage money, hold accounts, or give investment or tax advice. Every rate below was read out of the named IRS or Franchise Tax Board document on the date stated.

What a harvested loss is actually worth in California

California is unusual in a way that decides this whole question: it has no separate capital gains rate. Gains are taxed on the ordinary schedule, so the state's full marginal rate rides on top of whatever you owe federally. The Franchise Tax Board's 2025 Form 540 rate schedules put a single filer into the 9.30% band at $72,724 of taxable income, then 10.30% at $371,479, 11.30% at $445,771 and 12.30% above $742,953. The joint schedule reaches 9.30% at $145,448 and 12.30% above $1,485,906.

Above $1,000,000 of taxable income there is a further 1%, which is where the familiar 13.3% figure comes from. Worth noting because almost every article still has the old name: the 2025 Form 540 booklet states that "For taxable years beginning on or after January 1, 2025, the Mental Health Services Act has been renamed to the Behavioral Health Services Act. Therefore, references to the Mental Health Services Tax have been renamed to Behavioral Health Services Tax." Same 1%, same threshold, different line 62 heading.

Stack that on the federal side and the gap opens up fast.

Federal figures are the 15% long-term rate and the 32% ordinary rate from Rev. Proc. 2025-32 for 2026, plus the statutory 3.8% net investment income tax, which applies once modified AGI passes $200,000 single or $250,000 joint and is never indexed for inflation. A Californian in the 9.30% band gets 49% more out of an identical trade than someone in Texas. That is not a rounding difference, and it is the reason automated harvesting is worth paying for at portfolio sizes in California where it would not be worth the effort elsewhere.

Does the benefit actually cover the fee?

Here is where most comparisons stop being useful, because they list fees and list features and never put the two on the same axis. There is a way to do it with published numbers rather than vendor claims.

Wealthfront's tax loss harvesting whitepaper, backtesting February 4 2015 to December 31 2025, reports a harvesting yield of 3.61% for direct indexing against 2.60% for an ETF-only portfolio. The difference, 1.01% a year of extra losses harvested, is the incremental thing you are buying. Multiply it by the investor's marginal rate and you get the annual benefit as a share of account value. Wealthfront does exactly this and publishes the result as 0.18% to 0.44% a year at marginal rates of 18% to 44%, so the arithmetic below is their own, just extended to California rates and set against what each provider charges.

Read the last three rows carefully, because they are the finding. On harvesting alone, using the harvesting-yield number a direct indexing provider published about its own product, a 0.40% direct indexing account does not pay for itself even for a Californian in the top bracket. It may still be worth buying, but it has to be worth buying for something else: an adviser relationship, a custom benchmark, exclusions you cannot get elsewhere, or the ability to manage a concentrated position. It is not worth buying for the tax alpha.

Two honest caveats. Wealthfront's 1.01% covers a period containing the 2020 and 2022 drawdowns, and harvesting yield decays as an account ages and its cost basis falls, which is a real problem we have written about separately in what happens when there are no losses left to harvest. And the whole thing collapses to nearly nothing if you have no realized gains to offset, because the deduction against ordinary income is capped at $3,000 a year. Our tax loss harvesting calculator runs that netting properly for your own numbers, and the provider-by-provider fee and scanning-frequency detail sits on the tax loss harvesting software page.

Which platform is best for a California investor?

For most self-directed Californians, Frec and Wealthfront at 0.09% for S&P 500 direct indexing. Both charge the same headline rate, verified August 2026. Wealthfront starts at $5,000 and offers the S&P 500 or the Nasdaq-100; Frec starts at $20,000 and offers 25 indexes with daily harvesting checks. Above roughly $250,000, an adviser-channel SMA becomes worth quoting.

What none of these platforms will do for you

They cannot see your other accounts, and in California that is expensive. Schwab says so plainly in its own disclosure: it "does not monitor for wash sales in other accounts held by a client, and as a result wash sales may occur from trading in multiple accounts held by a client." Every other provider is in the same position. Your 401(k) buying an S&P 500 fund twice a month on payroll is invisible to them, and so is your spouse's brokerage account.

The consequence is worse than a deferred deduction when the replacement lands in a retirement account. Under Revenue Ruling 2008-5, a loss disallowed because the replacement shares were bought inside an IRA is not added to any basis anywhere, so it is forfeited outright rather than postponed. IRS Publication 550 says the same thing in a single parenthesis most people read straight past: add the disallowed loss to the cost of the new stock "(except in (4) above)", where (4) is the IRA case. At a 45.1% combined California short-term rate, a $20,000 disallowed loss that would merely have been deferred instead costs about $9,000 permanently. The wash sale calculator prices a specific trade before you place it.

The second gap is that none of these platforms asks what state you live in before it shows you a savings estimate. The numbers in their marketing are federal, which for a Californian understates the benefit by roughly a third. That cuts in your favor, but it also means you cannot take their estimate at face value in either direction.

How do I know my marginal rate before December 31?

You have to estimate it, because the harvesting decision has to be made before the year closes and the rate decides everything. Add your ordinary income, find your federal bracket and your California band, add 3.8% if modified AGI clears $200,000 single or $250,000 joint, and use the combined figure. Getting the band wrong by one step changes the answer by three points.

For a salaried employee that is a ten minute job. For the large share of high-earning Californians whose income runs through an S corporation, an LLC or consulting work, it is genuinely hard, because the number that decides the bracket is not knowable until the books are current. If that is you, the sequence that works is to close the year to date and get a real profit and loss statement out of your bookkeeping in November, then decide what to harvest in December against a number you trust rather than a guess. Harvesting into the wrong bracket assumption is how people end up with a large carryover they did not want and a $3,000 a year pipe to drain it through.

Is tax loss harvesting worth more in California than in other states?

Yes, by roughly 50% for a mid-bracket earner. California taxes capital gains at its ordinary rates with no preferential treatment, so the state's marginal rate is added in full to the federal one. A long-term loss worth 18.8% to a Texan is worth 28.1% to a Californian in the 9.30% band and 32.1% at the top with the 1% surcharge.

Does California have a lower long-term capital gains rate?

No. There is no long-term rate, no holding period discount and no separate schedule. The Franchise Tax Board applies the same 1.00% to 12.30% brackets to a gain held for ten years as to one held for ten days. The only rate distinction that survives in California is the federal one, which is why short-term harvesting is still the more valuable trade.

Can I use a California capital loss carryover the same way as federal?

Broadly yes, with the same $3,000 annual ceiling against ordinary income, but California tracks its own carryover balance separately and the two can diverge if any basis differences exist between your federal and state returns. Keep both figures. The federal rule is that a carryover keeps its short-term or long-term character indefinitely until used up.

The step worth taking first

Every provider above is selling you the same underlying mechanism: hold the index as individual stocks so that in a year the index rises, the several hundred members that fell are each a separate harvestable lot. What differs is the fee, the minimum, the index menu and how often the scan runs. Before paying anyone basis points to run that, it is worth knowing exactly which index you want held, which names you want excluded and how much tracking error you are willing to accept, because those are your decisions and they change which provider fits. Specify the index, test it against real market history, then go shopping. Our direct indexing fees page prices the alternatives with nothing hidden.

Sources

California Franchise Tax Board, 2025 California Tax Rate Schedules (Form 540), and the 2025 Form 540 booklet, line 62 instruction, both read 2026-09-06; the FTB had not published 2026 schedules as of that date. IRS Rev. Proc. 2025-32 for the 2026 federal brackets and long-term breakpoints. IRS net investment income tax thresholds, which are statutory and not indexed. IRS Publication 550 (2025) for the wash sale basis rule and the $3,000 capital loss deduction limit, and IRS Revenue Ruling 2008-5 for the IRA case. Wealthfront tax loss harvesting whitepaper, backtest February 4 2015 to December 31 2025, for the 3.61% and 2.60% harvesting yields and the 0.18% to 0.44% benefit range. Frec pricing and $20,000 minimum read from frec.com on 2026-09-06. Wealthfront S&P 500 Direct fee verified August 2026. Parametric Portfolio Associates LLC and Aperio Group, LLC, Form ADV Part 2A brochures dated 03/31/2026. Schwab wash sale disclosure read from schwab.com. Indexes is not affiliated with, endorsed by or sponsored by any firm named here, and none of them pays us anything.