Tax insurance in deals: what transactional tax policies cover

Tax insurance, also called transactional tax liability insurance, is a policy that pays if a taxing authority successfully challenges a specific tax position you have taken, such as the tax-free status of a reorganization or the validity of a target's S corporation election. It covers the extra tax, interest, penalties and the cost of defending the position, and it is bought once, up front, for a policy term that usually tracks the statute of limitations. It is built for deals, and it is placed by specialist brokers rather than through the commercial package a small business buys.

If you are buying or selling a company and your lawyers or accountants have flagged a tax issue that the other side will not simply absorb, this is the product that may let the deal close.

What a tax policy insures

The policy is written around one identified tax position, not a general promise that your taxes are right. Brokers describe the covered position as the trigger for loss. The positions below are the ones brokers and practitioners cite most often, drawn from a December 2025 Vanbridge overview and a March 2021 Tax Notes report on an Alston & Bird webinar.

• Deal structure. The validity of a Section 338 election, tax-free treatment of a Section 351 transfer, a Section 355 spin-off or a Section 368 reorganization.
• Identified diligence issues. Whether a target's net operating losses (NOLs) can be used, the tax consequences of an earlier restructuring, deferred compensation, or transfer pricing.
• S corporation status. Ineligible shareholders, disproportionate distributions, a second class of stock or a late election.
• Tax credits. Whether investment or production credits will be respected, or whether credits sold under Section 6418 will survive an IRS challenge.
• Audits and ongoing positions. A position already under examination, a REIT's status, or a partnership's return.

Federal rules for some energy credits changed in 2025 under Public Law 119-21, so a credit-based structure needs current tax advice before anyone prices it.

How it differs from R&W insurance

The two products are often bought together and often confused. Representations and warranties insurance covers breaches of the seller's promises that nobody knew about at closing. Matters the buyer already knows are excluded, and tax issues found in diligence are the usual example. Tax insurance fills that hole. The Tax Notes report calls it a bridge over the gaps in R&W coverage for identified and known risks.

A practitioner quoted in Tax Notes, William Kellogg of Berkshire Hathaway Specialty Insurance, pointed to the contrast with an indemnity backed by a two-year escrow. Insurance can also be less exposed to the credit risk of a seller or project sponsor.

What the policy pays, and what it will not

Brokers and practitioners describe the covered loss as the additional tax from losing the position, plus interest, penalties, the costs of contesting the issue, and a gross-up for income tax on the insurance proceeds themselves if the payment is taxable. The idea, Alston & Bird's Scott Harty said, is to put the insured where it would have been had the tax liability never arisen.

Expect exclusions for fraud, filings inconsistent with the covered position, material misstatements in the information given to underwriters, and changes in law. Per Vanbridge, tax insurance is generally available only if the transaction is not abusive or reportable under Treasury Regulation 1.6011-4. Tax Notes quotes an AIG underwriter saying insurers look for supportable positions with a reasonable basis that are not abusive, and Kellogg saying insurers are not betting on whether a return gets audited. Policies insure positions that are more likely than not to be upheld, usually on a written analysis from the insured's outside advisers, which the insurer tests with its own tax counsel. A formal opinion is not always required, but a written analysis of the facts, the issue and the conclusion is. Underwriters ask about motivation too. Kellogg noted that insurers can question a request to insure a strategy placed years after it was adopted.

Read the wording for who controls a contest with the tax authority, when notice must be given, whether the policy can be assigned to a lender or successor, and when a loss is payable. These vary by carrier.

Term, limits and cost

Treat the numbers below as one broker's published ranges rather than a rate card. Vanbridge, a tax insurance broker, states that premiums run between 2% and 5% of the limit purchased, charged once; policy terms run up to seven years to match the limitations period, with ten available for specific risks; limits run from $5 million to $1 billion or more; and retentions range from none to a deductible that applies only to defense costs. It reports over 20 carriers and roughly $1 billion of capacity for a single transaction. Marsh reported in its 2025 transactional risk review that tax insurance usage accelerated materially across regions.

The federal limitations period explains the term. Tax generally may be assessed within 3 years after the return is filed, 6 years if the return omits more than 25% of gross income, and at any time for fraud or a missing return (26 U.S.C. 6501). Brokers set the term to match the period in which the tax authority can still assess, which is why multi-year terms are standard.

Coverage is often written in the Lloyd's and other non-admitted markets, so a surplus lines placement may carry state tax and filing duties; ask your broker. See How Lloyd's of London works: syndicates, brokers and what it means for you and surplus lines taxes, stamping fees and diligent search.

The process, step by step

1. Identify the issue early. Diligence or planning surfaces a position that the tax advisers believe is more likely than not to hold.
2. Get the advisers' analysis in writing. Underwriters start from it.
3. Engage a specialist broker. The broker prepares a submission and markets the risk to insurers. See how to prepare an insurance submission underwriters will read and wholesale brokers and surplus lines placement: how hard risks get insured.
4. Underwriting. The insurer's underwriting team reviews the diligence and may retain its own tax counsel. Ask what underwriting fees are owed if you do not bind.
5. Negotiate the wording. Focus on the covered position, exclusions, the claims process and assignability.
6. Bind at or before closing. Vanbridge says markets can underwrite and bind in as little as two weeks, but complex positions take longer.

Kellogg advised involving the insurer on the front end, before the position is taken, rather than years afterward.

A hypothetical

Say a buyer agrees to purchase an S corporation, and diligence turns up a second class of stock problem that could end the S election. The R&W insurer excludes it as a known issue. The seller offers a two-year escrow as its indemnity, but the IRS can examine for longer than that. The buyer's tax counsel concludes the S election is more likely than not valid. The buyer purchases a $20 million tax policy with a seven-year term. At the broker-reported 2% to 5% range, the one-time premium would be roughly $400,000 to $1 million, before retention and fees; this is an arithmetic illustration, not a quote.

If the IRS later asserts that the election was invalid, the policy would be expected to respond to the corporate tax, interest, penalties, the cost of contesting the position, and the tax on the proceeds. The loss is subject to the limit and exclusions. A private letter ruling under section 1362(f) can sometimes repair an inadvertent termination, but as Kellogg noted, insurance can be bought faster, with the ruling request filed afterward.

When it fits and when it does not

It fits when a known, quantifiable tax risk is blocking a deal, when an escrow would tie up cash, or when the buyer wants an insurer's credit instead of a seller's. It is a poor fit for risks that are likely to lose, for transactions with no business purpose beyond tax benefits, or for positions the advisers are not willing to support in writing. For a smaller deal, weigh the broker and underwriting costs against the exposure, and see insurance due diligence when buying a business for the wider diligence picture. Tax advice, not this guide, decides whether a position works. Whether premiums are deductible or capitalized is another question for a CPA.

Key takeaways

• Tax insurance covers a specific, identified tax position in a deal, filling the known-issue gap that R&W insurance leaves.
• A policy pays additional tax, interest, penalties, contest costs and a gross-up, subject to exclusions for fraud, inconsistent filings and changes in law.
• Insurers write positions that are more likely than not to hold and are not abusive, based on written analysis from your advisers.
• One broker reports premiums of 2% to 5% of the limit, terms up to seven years and placement in as little as two weeks; treat these as ranges.
• Raise the issue early, use a specialist broker and read the claims, control and assignment provisions.