Supplemental Jurisdiction
Supplemental jurisdiction lets the Texas Business Court hear a related claim it could not have taken on its own, but only if every party agrees and the judge permits it. Section 25A.004(f) imposes both conditions. Unlike federal supplemental jurisdiction, a related claim cannot proceed on relatedness alone, and section 25A.004(h) puts several categories of claim out of reach entirely.
Federal practitioners arrive at the Texas Business Court with the wrong instinct. In federal court, supplemental jurisdiction under 28 U.S.C. § 1367 attaches by operation of law to claims forming part of the same case or controversy. The business court borrows the same relatedness test but adds a consent requirement.
Two consents, not one
Tex. Gov't Code § 25A.004(f) gives the court supplemental jurisdiction, in an action within its jurisdiction under subsection (b), (c), (d), or (e), over any other claim so related that it forms part of the same case or controversy. The claim may proceed in the business court only on the agreement of all parties to the claim and a judge of the division where the action is pending. Both are required. A unanimous party agreement does not bind the judge, and a willing judge cannot cure one holdout. Without agreement, the claim may proceed in a court of original jurisdiction alongside the related claims in the business court.
H.B. 40 was a substantial expansion of the business court in most respects. It reworded the first sentence of subsection (f), but the consent requirement survived the 2025 session unchanged.
Claims that cannot come in at all
§ 25A.004(h) operates as an absolute bar rather than a default. Health care liability claims under Chapter 74 of the Civil Practice and Remedies Code, claims for monetary damages for bodily injury or death, and legal malpractice claims are excluded. H.B. 40 moved into this list claims related to a consumer transaction to which a Texas consumer is a party and that arise out of a violation of state or federal law. Before September 1, 2025, those claims sat in subsection (g) and could come in through supplemental jurisdiction. Party agreement does not help. A judge's permission does not help. If the claim falls into one of those categories it belongs in district court, full stop.
That last addition matters to anyone drafting against a company with both commercial and retail exposure. A consumer's claim under the Deceptive Trade Practices Act cannot be dragged along behind a $20 million governance dispute.
The strategic shape of the rule
Because consent is required, supplemental jurisdiction functions as a one-party veto. A plaintiff whose case mostly fits § 25A.004(b) but includes a tag-along claim faces a choice. Seek consent and expose the request to a defendant who would rather split the case, drop the claim, or file everything in district court before a judge without a specialized commercial docket. Splitting has its own costs. Two proceedings on overlapping facts can produce inconsistent discovery rulings and a later dispute about preclusion.
Contracts can reduce the problem. Under § 25A.004(d)(2), parties to a business, commercial, or investment contract or transaction can agree that the business court has jurisdiction of actions arising out of it, though the amount in controversy must still exceed $5 million and actions arising out of insurance contracts are excluded. A broad clause may leave fewer claims needing supplemental treatment. The statute does not say whether a pre-dispute clause can supply the party agreement that subsection (f) requires.