Portfolio Trackers for Tax Decisions: Mezzi, Sharesight, and Monarch

Updated September 26, 2026.

The best portfolio tracker for a tax decision depends on what is missing: reliable records, a broader financial picture, or help interpreting the choices. Sharesight is a strong candidate for transaction-based investment performance and reporting. Monarch Plus adds investment detail within a household money-management workflow. Mezzi connects available account data with financial guidance and personal context.

A tracker is not automatically a tax-filing service or an investment manager. Before comparing optimization claims, establish what information the product receives and who will implement any change.

Method: Mezzi publishes this article. We reviewed official product documents on September 26, 2026, and use our Mezzi application review for context. We did not audit tax returns or test matched portfolios across all three products. The comparison concerns documented capabilities, record quality, and decision workflows. It does not predict savings.

Three roles, compared directly

1. Mezzi: interpret a potential change in household context

Mezzi can bring investments, banking, assets such as real estate, and liabilities including credit cards into a financial discussion. AI Personalization lets you save goals, constraints, and background that should inform advice. That broader context matters when a potential sale affects more than the investment account.

For example, you might be deciding whether to reduce a concentrated holding while reserving cash for an expense. A useful answer should consider the investment exposure, cash need, available account information, and assumptions about taxes. It should also identify what it cannot establish from the data supplied.

Tax-lot visibility is conditional

Mezzi's account-group and tax-lot update explains that lot information depends on the brokerage connection. A holding balance and a market price are not enough to establish the taxable gain on a particular lot. Acquisition date and adjusted basis can matter, as can activity the application does not receive.

Start by checking whether the relevant lots are visible and consistent with the brokerage. If they are not, treat that as an information gap rather than asking the assistant to infer a precise result. A complete-looking dashboard is not proof that the underlying records are complete.

Where personalization helps

A general tax idea can be inappropriate for a particular household. You may have a planned charitable gift, a near-term cash requirement, or a reason not to increase a particular exposure. Recording those circumstances helps make the discussion more relevant.

AI Personalization does not enforce a restriction at your brokerage. Active Delegations on paid plans are also distinct from trade execution. Confirm the scope of any ongoing task and the data it can use.

Cost and fit

Mezzi has a Free entry point; Advisory is $399 annually and Concierge is $999 annually. See plan details. Choose it when you want help interpreting the available information and are prepared to confirm and implement a decision. It does not place trades, transfer funds, file taxes, or certify that every household wash-sale risk has been eliminated.

2. Sharesight: establish the investment record behind the decision

Sharesight focuses on investment tracking, performance, dividends, and reporting. That makes it relevant when the difficulty is reconstructing what the portfolio earned or maintaining the records behind the result.

The practical value of a transaction-based approach is that investment performance can be separated from money you added or withdrew. For tax-sensitive decisions, the related recordkeeping also matters: a transferred holding with missing purchase information may require attention before a gain or loss estimate is useful.

Reports and plan coverage

Sharesight's US pricing currently lists Free for one portfolio and ten holdings, including closed positions. Annual paid plans list Starter at $84, Standard at $216, and Premium at $279. Holding, portfolio, and report allowances differ. Check the report you actually need rather than assuming every paid subscription includes it.

The product should also receive credit for its Exposure Report, which can examine underlying ETF exposure and overlap for supported investments. It would be inaccurate to describe Sharesight as incapable of looking through funds. Availability and data coverage should be checked for the particular portfolio.

Confirm the report's calculation method

Sharesight's U.S. investment-tax page describes its Sold Securities Report using an average-cost approach. Do not assume that output matches the basis method or specific lots appropriate to every U.S. security or your broker's sale instructions. Confirm the report's method and intended filing use with the relevant records and professional guidance.

For example, owning 100 shares bought at $10 and another 100 bought at $20 gives a simple average acquisition cost of $15 per share before adjustments. Selling 100 shares at $25 produces a $1,000 gain under that average illustration, versus $1,500 using the $10 lot or $500 using the $20 lot. Those different results explain why report conventions matter; the example is not permission to choose any method for any security.

A useful workflow

Start with one account and reconcile opening positions, purchases, sales, dividends, and transfers. Inspect any imported corporate actions and missing cost data. Then examine the report relevant to your question. This is a suggested reconciliation process, not a claim that every record must be entered manually or that all imports are error-free.

If you have investments in multiple currencies or jurisdictions, verify which reporting rules and conventions apply. A useful performance report is not automatically a tax return ready for filing in your country. Keep the institution's tax documents and professional review separate from the product's display.

Where it fits and where it stops

Sharesight deserves consideration when investment records and reporting are the central job. It may be a better first purchase than a conversational advisor if your historical data is disorganized. If you want a discussion linking investments to debt, spending priorities, and personal preferences, evaluate that broader guidance need separately.

Neither a well-reconciled record nor a report automatically decides whether you should sell. It supplies evidence for the decision. The investment reason, tax circumstances, and implementation still need to be considered.

3. Monarch Plus: connect investment detail to household money management

Monarch is relevant when investment decisions sit alongside budgeting, cash flow, and shared household goals. Its Plus guide describes deeper investment analysis, including gains-and-losses views with optional tax-lot detail, as well as forecasting and other features.

This means a comparison should not dismiss Monarch as only an expense tracker. It also should not assume that a visible tax-lot field provides all the information needed to recommend a sale.

Where the household context is useful

Suppose a household needs cash for a planned expense. The first question may be whether the spending plan and existing cash cover it. Only then does the question move to which investment might be sold and what the implications could be. A household money-management workflow can help clarify the first part of that sequence.

The investment view can then add detail, depending on the account data available. Verify connection coverage and the specific fields supplied. Any gains or losses should be checked against the underlying brokerage, especially for transferred holdings or incomplete history.

Plan and platform distinctions

Current pricing lists Core at $99.99 annually and Plus at $199.99 annually. Review the Plus guide for feature availability. Core and Plus are different offers, and newer Plus capabilities may have desktop and mobile differences. An introductory discount is not the same thing as the ongoing annual price.

If you already use Monarch for household finances, test whether its investment detail meets your needs before adding a separate tracker. That is a practical way to avoid redundant subscriptions. If you need an investment-record specialist or personalized financial guidance, compare those outputs directly rather than expecting one interface to do every job.

Where it stops

A financial-information product can display and organize data without providing an individualized tax recommendation or executing a trade. Keep those responsibilities distinct. A tax export should still be reviewed for the intended filing use, and the quality of the output depends on the records supplied.

The records to check before a tax-sensitive sale

A useful review starts with the actual security, account, quantity, acquisition dates, and adjusted basis. Confirm whether the figures are estimates, imported data, or institution records. If a holding was transferred between brokers, check that the history followed it accurately.

Then review relevant activity beyond the holding itself. Automatic reinvestments, recurring purchases, and related-account transactions can affect the analysis. The IRS discussion in Publication 550 explains capital gains, losses, and wash-sale rules. Do not treat an application label as a replacement for the underlying rules.

Finally, identify the implementation step. If specific lots are intended, confirm the broker's procedure and the resulting trade confirmation. A software suggestion and the transaction ultimately recorded by the broker can differ if the order is not entered as intended.

Why cost basis matters more than a red or green number

Consider a hypothetical holding now worth $20,000. If the relevant adjusted basis is $15,000, the simplified unrealized gain is $5,000. If the basis is $23,000, the simplified unrealized loss is $3,000. The market value is identical in both cases, but the tax starting point is different.

Those calculations omit lot selection, holding periods, fees, adjustments, and other tax rules. They show why a current balance alone cannot establish tax impact. Before comparing which AI explanation sounds best, verify the information both explanations use.

A useful combination, if each tool has a job

Some investors may want both detailed records and ongoing guidance. For example, a reporting tool could help maintain the investment history while a financial-advice workflow helps interpret a proposed change in household context. That combination is optional, not a recommendation to buy two subscriptions by default.

The most efficient setup is one you can keep accurate. If two dashboards contain conflicting balances and neither is reconciled, the extra software has not improved the decision. Establish a source of truth for records and keep the reasoning traceable to it.

Frequently asked questions

Which tracker is best for tax optimization?

Choose around the missing task. Sharesight is worth evaluating for investment records and reports; Monarch Plus for investment detail within household finances; Mezzi for guidance using available data and personal context. None should be assumed to perform every tax-related task.

Does Sharesight show ETF overlap?

Its Exposure Report documents underlying ETF exposure and overlap for supported investments. Check report access and coverage for your plan and holdings rather than assuming it is absent or universal.

Does seeing tax lots mean an app can execute the right sale?

No. Data visibility and execution are separate capabilities. Confirm who places the order and how the broker records the selected lots. Mezzi does not execute trades.

Can a tracker replace a tax return review?

Not by default. Reports and exports can support recordkeeping, but filing requirements, adjustments, and individual circumstances still need to be addressed. Verify the scope of the product and the intended use of the report.