Do I Have to Disclose Non-Marital Assets During My Divorce?

Before you get married, all of your property belongs to you and you alone. This includes your car, your bike, your house, and your income. After you get married, however, any new property you acquire is no longer just yours – it belongs to the marriage. (That is, if you do not have a prenuptial agreement in place. If you have a prenup, the remainder of this post will not apply to you.) Your income, your new car, and your new collection of rare vintage vinyl likely all belong to the marriage. That means that if you get divorced, all of that marital property will be split between you and your ex.

It makes sense that you need to disclose all of your marital property so that it can be fairly divided during a divorce, but do you also have to disclose assets that are clearly non-marital? After all, if an inheritance or pre-marriage bank account is yours alone, why should the court or your spouse need to know about it?

Disclose Everything in an Illinois Divorce

In Illinois, the short answer is yes—you do have to disclose non-marital assets during your divorce. The Illinois Marriage and Dissolution of Marriage Act (IMDMA) requires complete financial disclosure, and courts take this duty seriously. Even if an asset will never be divided, it must still be identified, disclosed, and proven to be non-marital. If you fail to disclose everything, you can face severe consequences, including sanctions (fines) and having property automatically classified as marital.

Marital Property and Non-Marital Property

Under Section 503(b)(1) of the IMDMA, the default assumption is that all property acquired during the marriage is marital. This presumption can be overcome by providing evidence that the asset qualifies as non-marital under Section 503(a).

The statute lists several categories of non-marital property, including:

• Property acquired before the marriage
• Property acquired by one party by gift or inheritance
• Property acquired in exchange for non-marital property
• Property excluded by valid prenuptial or postnuptial agreement

The IMDMA also requires the trial court to make specific factual findings regarding the classification of each asset. In a contested divorce, courts must determine whether an asset is marital or non-marital, assign value, and explain the reasoning behind its distribution. If an asset is never disclosed, the court cannot make these findings, and the failure to disclose may backfire against the spouse seeking to protect their assets.

Discovery and Disclosure Obligations

This is why complete and honest disclosure is baked into the divorce process. Under Illinois Supreme Court Rule 213 and local circuit court rules, all parties to a divorce or other family law matters (child support, etc.) are required to provide full disclosure of financial information through sworn financial affidavits listing all assets and debts—both marital and non-marital.

Failure to disclose can result in sanctions, exclusion of evidence, or even adverse rulings. Importantly, a spouse cannot later raise the “non-marital” classification if they failed to disclose the asset during discovery.

Case Study: In re Marriage of Xinos (2025)

The case of In re Marriage of Xinos, 2025 IL App (1st) 232326 is a cautionary tale for anyone tempted to keep non-marital assets “off the radar” during divorce proceedings. The husband in that case failed to properly disclose and substantiate his claim that certain accounts were non-marital, and the courts ultimately treated them as marital property.

During the divorce proceedings, Wife sent Husband a request for bank statement from all of his bank accounts as well as documentation of any property he was claiming to be non-marital. Husband did not produce any documents in response. He had thirteen bank accounts, some of which he tried to claim were non-marital property during his trial. By then it was too late, however, because he had never provided any documentation of these accounts before trial, and was thus barred from doing so.

Husband appealed this ruling and claimed that his attorney did not provide him with effective counsel.

The Appellate Court agreed with the lower Court that Husband’s accounts should be considered marital property because he had not disclosed what parts of them he claimed to be non-marital.

The appellate court emphasized:

• Burden of Proof – The spouse claiming property as non-marital must provide clear and convincing evidence. Husband failed to provide bank records or documentation.
• Sanctions for Discovery Failures – The trial court acted within its discretion in sanctioning Husband by barring evidence due to his discovery failures.

Ultimately, the accounts were treated as marital property and divided accordingly.

The Xinos decision highlights several lessons:

• Courts will not accept a spouse’s word that an asset is non-marital without documentation.
• Discovery violations can prevent you from ever presenting your non-marital claims.
• Failing to disclose can result in permanent forfeiture of property rights.

Why You Must Disclose Non-Marital Assets

Even if you believe an asset is unquestionably yours, Illinois law requires disclosure for several reasons.

Ensuring Fairness and Transparency

Full disclosure ensures that both parties and the court have a complete financial picture. This is essential for equitable division of marital property, even if the non-marital property itself is not divided.

Avoiding Sanctions and Forfeiture

As Xinos shows, failure to disclose can lead to evidence being barred, assets being classified as marital, and claims being forfeited.

Addressing Commingling and Reimbursement

Sometime, non-marital assets can be affected by marital contributions. For example, if marital income was used to pay down a mortgage on a premarital home, the marital estate may have a reimbursement claim. Without disclosure, you risk losing the ability to properly trace and address these contributions.

If you want to preserve your non-marital property rights during a divorce, consider the following best practices:

• Disclose All Assets – Include every asset, whether you consider it marital or not, on your financial affidavit.
• Gather Documentation Early – Collect deeds, bank records, inheritance papers, and other proof to show when and how the asset was acquired.
• Work with Experts if Necessary – For complex tracing, consider hiring a forensic accountant to establish the source of funds.
• Avoid Commingling – Keep non-marital assets separate. Mixing them with marital funds can convert them into marital property.
• Respond Promptly in Discovery – Comply with all requests for production and interrogatories to avoid sanctions.
• Present Evidence at Trial – Do not rely on assumptions; the court needs admissible evidence.

Seek Legal Guidance

In Illinois, the answer to the question “Do I have to disclose non-marital assets during divorce?” is an unequivocal yes. The IMDMA requires full financial disclosure, and the burden of proof lies squarely with the spouse claiming non-marital status.

The classification of property can be complicated, and legal advice is crucial to protecting your interests. If you need help dividing a complex or high-asset marital estate, the experienced attorneys at O. Long Law, LLC, are here to help. Reach out to us today to schedule your initial consultation.