Short answer

If a trustee’s sale produced money in excess of the amounts owed, that excess (the “surplus” or “overage”) belongs to the person or estate that held title. In California the first practical steps are: (1) confirm the type of foreclosure and whether a surplus exists; (2) gather proof of your legal right (for a deceased owner, proof you are the executor/administrator or an heir); (3) make a written claim to the trustee or sale agent; and (4) if the claim is refused or others dispute it, file a court action in superior court asking the court to determine entitlement to the surplus. Civil Code section 2924k governs surplus proceeds from a nonjudicial trustee’s sale: https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?sectionNum=2924k.&lawCode=CIV

Detailed answer — step‑by‑step (what to do now)

1) Confirm the foreclosure type and whether surplus exists

Foreclosures in California are usually nonjudicial (trustee’s sale under a deed of trust). Surplus money arises when the sale price exceeds the sums due (mortgage balance, trustee fees, sale costs). Start by getting information from the trustee who conducted the sale, the agent who advertised the sale (often a title company), or the county recorder (to obtain the Trustee’s Deed Upon Sale or sale statements). The trustee’s sale paperwork will show gross sale proceeds and the payoff figures.

2) Who is entitled when the owner is deceased?

If your mom is deceased, the person with legal authority to claim the surplus is the decedent’s personal representative (executor or administrator) or, if there is no probate, someone who can prove heirship under California law. If an estate has been opened and someone has letters testamentary or letters of administration, that person can claim the funds. If no probate exists, heirs may need to open probate or use another estate procedure (for small estates) to obtain authority to claim assets.

3) Gather the documents you will need

• Trustee’s Deed Upon Sale, sale statement, or other foreclosure sale paperwork.
• Deed showing that your mom held title before the sale.
• Your mom’s death certificate.
• If there is a probate: letters testamentary or letters of administration and the estate case number.
• If no probate: an affidavit of heirship or documents that show you are an heir (birth certificate, family records) — but courts and banks typically require formal probate authority.
• Government ID for the person making the claim and a written demand for the surplus.

4) Make a written claim to the trustee/sale agent

Send a written demand to the trustee or foreclosure sale agent identifying the sale, stating the amount you believe is due, and attaching proof of your claim (death certificate, letters, deed, etc.). Keep proof of delivery. Trustees often will pay a rightful claimant if the claim is uncontested and proof is satisfactory.

5) If the trustee refuses or others claim the funds: file in Superior Court

If the trustee rejects your claim or multiple parties claim the surplus, you will need a court determination. That typically means filing a civil action in the California Superior Court in the county where the property was sold asking the court to determine who is entitled to the surplus proceeds. In practice this can be titled a “Complaint/Petition for Determination of Right to Excess Sale Proceeds” or a similar pleading. In that action you will:

• Plead the facts: ownership, foreclosure sale, amount of surplus, why you (or the estate) are entitled.
• Attach supporting documents (trustee’s deed, death certificate, letters, chain of title, proof of demand on trustee).
• Serve all potential claimants and the trustee according to court rules.
• Ask the court for an order directing the trustee (or the court clerk, if funds are deposited) to pay the surplus to the rightful party.

The court will evaluate competing claims and then enter an order distributing the funds. If the trustee already deposited the funds with the court or county treasurer, the court can order distribution from that account.

6) Practical issues when the owner is deceased

If your mom’s estate is open and you are the executor/administrator, present your letters to the trustee and the court action should be straightforward. If no probate exists, you will likely need to open probate or use the available small estate procedures so you have legal authority to receive estate assets. Courts and trustees are reluctant to hand surplus funds to someone without formal authority.

7) Timing, costs, and realistic expectations

There is no single fixed timeline for resolving disputed surplus claims: uncontested claims can be resolved in weeks; contested cases may take months and require court filings and possibly a hearing. Expect filing fees, service costs, and potentially attorney fees if you hire counsel. If the proceeds are small, weigh the cost of litigation versus the amount recoverable.

8) Key California law reference

California law recognizes surplus proceeds after a trustee’s sale and the need to pay the trustor or other entitled parties. For nonjudicial trustee’s sale surplus rules see California Civil Code §2924k: https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?sectionNum=2924k.&lawCode=CIV

Helpful Hints

• Act early. Get sale paperwork and act before funds are distributed or claimants disperse.
• Contact the trustee first. Some trustees will pay a clear, documented claim without court involvement.
• Obtain certified copies. Get certified copies of the deed, trustee’s deed, and the death certificate to submit with claims.
• If probate exists, present letters of administration/testamentary. Courts and trustees prefer formal executor authority.
• If there is no probate and the surplus is small, ask a lawyer about small estate procedures before filing a full probate.
• Keep a clear paper trail: written demands, proof of service, and receipts.
• Check county records online. Many counties list trustee deeds and sale results through the recorder’s office or trustee’s website.
• Consult a lawyer if other claimants appear, the trustee won’t pay, or if heirs dispute the distribution.