How Does Tax-Loss Harvesting Work and How Can It Fund a Portfolio Transition for RIA Clients?

Tax-loss harvesting sells securities that have fallen below cost to realize a loss, then reinvests in a similar but not identical holding so the portfolio stays near its target. The realized losses offset capital gains, which lets an RIA sell a new client's appreciated legacy positions and move into a model sooner than a flat tax limit would allow.

What Does Tax-Loss Harvesting Mean in Tax-Managed Investing for RIAs?

The mechanics have four parts: a lot is sold below cost, the loss is realized, the proceeds move into a similar holding, and the loss is netted against gains. The steps below show how each part works.

How Tax-Loss Harvesting Works, Step by Step

A holding trades below its cost basis, which creates an unrealized loss in a specific tax lot.
The portfolio sells that lot and realizes the loss.
The proceeds go into a similar but not identical security, so market exposure stays close to the target allocation.
The replacement purchase avoids a wash sale, which would disallow the loss.
The realized loss is netted against the client's capital gains for the year, and any excess carries forward.

Most descriptions stop there and treat harvesting as a year-end task or a feature of a direct index sleeve.

For an RIA onboarding a client with large unrealized gains, harvesting has a second job. Losses harvested in the account can offset the gains realized when a legacy position is sold. That lets the firm move the client into a new model faster than a flat tax limit would allow, so harvesting becomes a way to fund the transition as well as a source of tax savings.

Evaluating a harvesting strategy on that basis means looking at how often accounts are screened, whether the strategy runs inside a tax budget the client chose, and whether harvested losses are applied to the gains that actually need to be offset.

What Should RIAs Expect from Tax-Loss Harvesting Strategies?

Most providers can say they harvest losses, so a feature list does little to separate them. The differences show up in how often accounts are screened, what a harvested loss is netted against, and who sets the limits. For an RIA, those choices decide whether a harvest produces a tax benefit the client can use or a loss that sits unused in one sleeve. They also decide whether harvesting can pay for a move into a new model when a client holds large embedded gains.

The table below lists the eight dimensions to evaluate, what each one enables, and why it matters for an RIA's practice.

Evaluation Dimension	What It Enables	Why It Matters for RIAs Specifically
Screening cadence	Every taxable account is checked for harvestable losses on a set schedule, so losses are captured closer to when they occur	An RIA's book includes hundreds of taxable accounts. A quarterly or year-end cycle misses losses that appear and recover between reviews, and advisors cannot screen that many accounts by hand
Account-level scope	Losses and gains are netted across every sleeve in the account, so a loss in a direct index sleeve can offset a gain in an SMA or fund	Clients hold several strategies in one account. Sleeve-only harvesting leaves the client paying tax on gains that losses elsewhere in the account could have offset
Tax budget control	Harvesting and gain realization follow a dollar amount the client has agreed to pay for the year	The advisor can ask the client what they are willing to pay in taxes this calendar year and get an answer the program enforces, in place of a flat percentage limit applied to every account
Tax rate accuracy	Decisions use the client's own federal and state rates for short-term and long-term gains	A loss is worth a different amount to a client in a high-tax state than to one in a state with no income tax. A generic top-bracket assumption misstates the value for both
Transition support	Harvested losses are applied against the embedded gains in legacy holdings as they are sold	New clients often arrive with appreciated positions. Harvesting that funds the move shortens the time to the target model, which affects how quickly the RIA can deliver the portfolio it proposed
Wash sale discipline	Replacement purchases are checked against harvests in other accounts in the same household	A repurchase in a spouse's or related account can disallow a loss. The client will hold the advisor responsible for that outcome, so the check has to cover the household and not only the account
Risk guardrails	Harvesting stays within limits on concentration and drift from the model	The RIA is accountable for the integrity of the model. Tax savings that pull accounts away from it create tracking and suitability conversations the advisor did not plan for
Advisor control	Advisors can request a harvest or change a tax budget mid-year without suspending the account	Client circumstances change during the year, such as a business sale or an inheritance. The advisor needs to respond without the account going dark while the change is processed

How Do RIAs Set Up Tax-Loss Harvesting in a Taxable Portfolio?

Setting up harvesting comes down to a short list of settings, and most of them describe the client and not the market. The budget and the client's tax rates come first because they set the value of every trade.

Restrictions, guardrails, and a loss threshold come next because they control the risk and the cost. Once those are in place, the overlay does the screening, so advisors do not review accounts one at a time.

Setting	What It Controls	How VAST Handles It
Tax budget or Tax Reserve	The dollar amount the client can set aside to pay capital gains tax in the current calendar year	The advisor enters a capital gains budget or Tax Reserve. It stays in force after the account reaches its model, can be revised during the year, and carries into later years unless the advisor changes it
Tax rates	The value of each harvested loss and each realized gain	Decisions use the client's own federal and state rates for short-term and long-term gains
Client restrictions	Securities the client does not want bought or sold	Holdings carrying a do-not-sell restriction are excluded from the harvest calculation, and restrictions and values-based screens are enforced at the account level
Weight guardrails	How far harvesting can pull the account away from its model	Active weight guardrails keep harvesting from overselling the largest holdings, and the optimizer seeks the lowest tracking error available within the client's budget
Minimum loss threshold	How large a loss must be before a sale is worth the trading cost	Losses are evaluated at the tax lot level against a minimum threshold. Accounts in transition are searched for lot-level losses that meet a minimum threshold in aggregate
Screening schedule	How often the account is checked for harvestable losses	All taxable portfolios are screened daily, whether the account is at model or in transition

How Much Can Tax-Loss Harvesting Offset, and When Should Losses Be Realized?

Harvested losses offset capital gains dollar for dollar, and there is no cap on the amount of gains they can offset. The limit is the amount of loss the account has available to realize.

How Losses Are Netted

Short-term losses first offset short-term gains, and long-term losses first offset long-term gains
A net loss in one category then offsets the net gain in the other
If total losses exceed total gains for the year, up to $3,000 of the net loss ($1,500 for a married person filing separately) can offset ordinary income (Source: IRS Publication 550, Investment Income and Expenses).
Any remaining loss carries forward to future tax years

Why Short-Term Gains Matter Most

Short-term gains come from positions held one year or less and are taxed at ordinary income rates. Long-term gains are taxed at lower federal rates (Source: IRS, Topic No. 409, Capital Gains and Losses). A dollar of loss that offsets a short-term gain usually saves more tax than a dollar that offsets a long-term gain, and state tax adds to the difference.

That is why VAST uses the client's own federal and state rates for both holding periods.

What Harvesting Does and Does Not Change

The replacement holding is bought at a lower price, so it carries a lower cost basis and a larger gain when it is eventually sold. In many cases harvesting defers tax and does not remove it. The benefit comes from paying the tax later and from any difference between the rate at which the loss offsets a gain today and the rate at which the later gain is taxed.

Can Harvested Losses Reduce Taxes on Stock Sales?

Yes. A loss realized in the same tax year offsets the gain from a stock sale, including the sale of a concentrated position. For a client with a large appreciated holding, the losses already in the account rarely cover the whole gain. This is where the Vestmark transition process applies.

VAST searches an account in transition daily for lot-level losses that meet a minimum threshold in aggregate. When they do, the account is rebalanced so those losses offset the gains realized from selling non-model holdings as proceeds move into the model. The client's budget sets the pace, so the prospect can see what will be sold this year and what it will cost.

When Should Losses Be Realized?

A loss only helps once it is realized, and it counts for the tax year in which it is realized. Prices move, and an opportunity open on one day can be gone the next. A year-end review captures the losses present on that date.

Daily screening captures losses as they appear, so they are available when a gain is realized, whether that gain comes from a planned sale during the year or from a transition.

How Does Tax-Loss Harvesting Differ in Direct Indexing vs. Funds?

Direct indexing and funds both support harvesting, but they give an advisor different amounts to work with. A direct index account holds the individual securities of an index, so each one has its own tax lots. A fund holds those securities inside a single share, so the client sees one position.

The comparison changes in a unified managed account. In VAST, direct indexing, SMAs, model portfolios, mutual funds, and ETFs can sit in one account, and tax decisions are coordinated across the sleeves. A loss harvested in the direct index sleeve can offset a gain realized in a fund or an SMA in the same account. Harvesting that stops at the edge of the direct index sleeve cannot do that.

Dimension	Direct Indexing	Funds and ETFs
What the client owns	Individual securities, held directly in the account	Shares of a fund that holds the securities
Tax lots available	Many lots across many securities	One position per fund, with lots based on purchase dates
Where losses come from	Individual stocks that fall below cost, even when the index rises	The fund's share price falling below cost
Harvest trade	Sell the lot and buy a similar security or let the optimizer rebalance within the index	Sell the fund and buy a different fund with similar exposure
Customization	Restrictions, factor tilts, and values-based screens can be applied at the security level	Limited to the choices the fund offers

How Do Automated Accounts Avoid Wash Sales?

A wash sale occurs when an investor sells a security at a loss and buys the same or a substantially identical security within 30 days before or after the sale. The loss is disallowed for the current year. The disallowed amount is added to the cost basis of the new shares, so the benefit is delayed and not erased. The rule also applies across accounts, including a spouse's account and an IRA.

An automated account avoids wash sales in two ways:

The replacement is a similar but not identical security, so the account keeps its market exposure without repurchasing what it sold
Purchases are checked against recent harvests in other accounts that could trigger the rule

In VAST, the optimizer avoids proposing a purchase of a security that another account in the household harvested within the past 31 days. Accounts that could create a wash sale against each other are flagged before trades are released. Any program can check only the accounts it can see, so RIAs should ask which accounts a provider covers and how far back the check looks.

Why Does Tax-Loss Harvesting Matter for RIAs Using Tax-Managed Investing Solutions?

Harvesting touches several systems and teams at once, including:

Custodian feeds that supply cost basis and tax lot data
The optimizer that proposes sells and replacement buys
The model or strategy the account is tracking
Client restrictions and values-based screens
Household and account group structures
Reporting that shows realized gains and losses year to date

Without coordination across those pieces, RIAs often experience:

Losses sitting unused in one sleeve while another sleeve realizes gains
Legacy positions held for years because the tax cost of selling them looks too high
Harvests that conflict with client restrictions or create wash sales
Advisors who cannot answer a client's question about how much tax was saved or deferred
Year-end rushes to harvest after the best opportunities have passed

How Is Tax-Loss Harvesting Changing, and Where Do Solutions Break Down for RIAs?

Harvesting used to be a calendar event. Advisors reviewed accounts in the fourth quarter, took the largest losses, and moved on. That cadence misses losses that appear and recover between reviews.

Several shifts are turning harvesting into a continuous process:

Screening is moving from quarterly or monthly reviews to daily
Tax limits are moving from a percentage of gains to a dollar amount the client is willing to pay
Harvesting is moving from a direct indexing feature to an account-wide function
Portfolio transitions are being treated as a harvesting use case, with losses applied to legacy exits
Advisors are expected to show the tax value delivered, in addition to describing the strategy

Solutions that have not made those shifts tend to break down in five places:

Single-sleeve scope: harvesting confined to a direct index sleeve cannot net against gains in the SMAs, funds, or legacy holdings next to it
Calendar-driven review: a loss that opens and closes between review dates is gone
Percentage-based gain limits: advisors recalculate by hand whenever the client's circumstances change
Account suspension to change terms: revising a budget can erase an existing transition plan and force the setup to be repeated
Replacement purchases without visibility: an account optimized in isolation can repurchase what another account just sold at a loss