If a probate sale goes to court confirmation, someone can show up and bid against the accepted offer. Buyers and agents both quote the minimum overbid as “ten percent.” That is not the rule, and the difference on a typical Bay Area property is substantial.
The actual formula
Probate Code §10311(a)(1) sets the minimum first overbid at 10% of the first $10,000, plus 5% of the amount above $10,000.
On a $1,000,000 accepted offer, that is 10% of $10,000, which is $1,000; plus 5% of the remaining $990,000, which is $49,500. The required increment is $50,500, so the minimum first overbid is $1,050,500.
A flat ten percent would have said $1,100,000. The gap is $49,500 — enough to change who wins.
And note which section this is. It is §10311(a)(1), not §10309. I see §10309 cited for the overbid formula regularly; §10309 is a different rule entirely, covered below.
The part that genuinely surprises people
Subsequent increments are not statutory. The code sets the first overbid. After that, the increments are at the judge’s discretion, announced in the courtroom, and they vary.
This matters if you are bidding. You cannot model the auction in advance from the code, because after the opening bid the rules of the room are set by whoever is on the bench that morning. Plan a ceiling, not a sequence.
One more detail worth knowing: under §10311(e), bids are computed without regard to commission. The commission arrangement does not change the bid arithmetic.
§10309 is the other rule, and it is about price, not bidding
Probate Code §10309(a) is the 90%-of-appraisal rule: the sale price generally must be at least 90% of the appraised value. It carries two one-year tests, and both are measured to the date of the confirmation hearing — not to the date of the offer, and not to the date of death.
Critically, §10309 does not apply to a full-authority IAEA sale. If the personal representative has full authority under the Independent Administration of Estates Act, that sale is not going through confirmation, and the 90% floor is not the governing constraint.
Which is why the authority question comes first
Before any of this matters, find out what authority actually exists:
- §10511 — full IAEA authority permits a sale without court confirmation.
- §10501(b) — limited authority still requires court approval for real property. §10503 lists what limited authority removes.
- §10501(a)(5) — court supervision is required where the buyer is the personal representative or their attorney, whatever the authority.
- §10586 — a Notice of Proposed Action requires not less than 15 days, and any interested person may object, which pulls the sale back in front of the judge.
And most sales here are not probate sales at all
The majority of the estate properties I am called about are held in a living trust, and a trustee’s sale generally needs no court confirmation whatsoever — Probate Code §16226. No overbid, no hearing, no 90% floor.
Court involvement in a trust sale is exception-driven: the instrument withholds the power of sale, co-trustees deadlock, a beneficiary contests, there is no trustee in office, the property was never actually funded into the trust (a Heggstad petition under §850), or the trustee wants cover for a sale that looks self-dealing (§17200).
So the first question is never “what is the overbid?” It is “is this a trust sale or a probate sale, and what authority does the representative hold?” That walkthrough goes through both paths in order.