Appellant Jean Leonard Harris (“Harris”) was the petitioner-debtor in a now-closed Chapter 7 bankruptcy case. Here, he sued the bankruptcy trustee and other estate representatives for breach of contract. Harris alleges the bankruptcy trustee and her agents breached a contract that was entered into during the course of his underlying bankruptcy case and was directly related to the administration of bankruptcy estate assets.
This appeal requires us to answer whether the bankruptcy court had subject matter jurisdiction over this state law breach of contract claim, and whether the bankruptcy court’s approval of the acts Harris now alleges breached the contract entitle the defendants to derived quasi-judicial immunity. We answer yes to both questions and so we affirm.
I. Factual and Procedural History
In July 1999, appellant Harris filed a voluntary petition for bankruptcy relief under Chapter 7 of the United States Bankruptcy Code in the United States Bankruptcy Court, Southern District of California. The bankruptcy court appointed appellee Sandra Wittman (‘Wittman”) as trustee of the bankruptcy estate (the “estate”) shortly thereafter. In March 2000, Wittman filed an adversary proceeding against Harris and his wife, Mrs. Harris, for fraudulent conveyance. Wittman’s complaint alleged the transfer from Harris to Mrs. Harris in June 1999 — the month before he filed his voluntary bankruptcy petition — of a 1957 Mercedes-Benz, as well as a storage business and related property called Alpine Personal Storage *735 (the “Alpine property”), was voidable and recoverable by the estate.
Trustee Wittman then entered into an Agreement for Use and Assignment of Interests and Prosecution of Claims (the “Assignment Agreement”) with appellee Jack Swain, an unsecured creditor of the estate, which assigned to Swain the right to prosecute the adversary proceeding to set aside the alleged fraudulent conveyance. In exchange, Swain was to be paid 68% of the net recovery he obtained, and to be reimbursed for any of his costs. The Assignment Agreement also specified that Swain’s counsel — the law firms of Pyle, Sims, Duncan & Stevenson, APC; and Grant & Zeko, APC (the “Attorney defendants”) — would be entitled to recover their attorneys’ fees from the estate. Wittman filed a motion for the bankruptcy court to approve the Assignment Agreement and appoint Swain as Special Representative of the estate. Harris received notice of the time and place of the motion. The bankruptcy court granted the motion, specifically approving all aspects of the Assignment Agreement, including the Attorney defendants’ attorneys’ fees.
In November 2002, Harris, Mrs. Harris, Sandra Wittman, and Jack Swain executed a written agreement that settled all the proceedings in the case (the “Settlement Agreement”). The bankruptcy court approved the Settlement Agreement in January 2003. According to the terms of that agreement, Harris and Mrs. Harris were required to transfer title to the Alpine property and the 1957 Mercedes-Benz to the bankruptcy estate. However, Mrs. Harris retained an allowed secured claim for $218,000 as a lien against the Alpine property. Further, Wittman was not to sell the Alpine property unless the sale would yield sufficient funds to pay Mrs. Harris’s said secured claim in full. As a final matter, the parties agreed to execute written mutual releases of any and all claims each had against the other that had arisen as of the date of the execution of the Settlement Agreement. A written release between Swain and Wittman, on the one hand, and Mr. and Mrs. Harris, on the other, was executed on November 22, 2002. The written release stated “the Parties agree this Agreement is a complete release of all claims the Parties have against one another arising from the ... Bankruptcy.”
On May 2, 2003, Wittman filed a Notice of Motion and Motion for Sale of Personal Property under 11 U.S.C. § 363(b), seeking an order permitting her to sell the Alpine property and the 1957 Mercedes-Benz to Swain. In support of her motion, Wittman filed a sworn declaration that stated the sale would be in the best interest of the bankruptcy estate because Swain would pay the estate $125,000; pay Mrs. Harris’s $218,000 claim at the close of the sale of the Alpine property to satisfy her secured claim against the Alpine property, thereby relieving the estate of this liability; waive Swain’s own claims against the estate for his costs and fees from the fraudulent conveyance proceeding; and assume the estate’s liability for the attorneys’ fees of the Attorney defendants. Altogether, Swain’s waiver of claims and assumption of liability totaled around $900,000. Wittman’s notice of sale set out a detailed accounting of the source of the estate liabilities that Swain was assuming. As in all noticed bankruptcy motions, Harris received notice of this motion.
The bankruptcy court approved the sale after a hearing on June 30, 2003. The court noted that the sale was free and clear of Mrs. Harris’s secured claim and that Jack Swain was to pay her claim in full at the close of the sale of the Alpine property. 1 Almost three years la *736 ter, on May 2, 2006, Harris filed the present suit in California state court in the Superior Court for the County of San Diego. He alleged breach of contract, breach of fiduciary duty, fraud, negligent misrepresentation, and constructive fraud. Harris alleged that Wittman, Swain, and the Attorney defendants breached the Settlement Agreement in two ways: (1) by agreeing that Swain and the Attorney defendants were entitled to approximately $1 million in “contrived claims” against the estate stemming from the fraudulent conveyance proceeding because those claims had already been released by the Settlement Agreement, and (2) by Witt-man’s sale of the Mercedes-Benz and the Alpine property to Swain in exchange for $125,000 and the release of the one million in “contrived claims.”
On May 15, 2006, Wittman successfully removed the case to the bankruptcy court that was administering Harris’s estate. Harris filed a motion for remand, which was denied. All of the defendants filed motions to dismiss the complaint under Federal Rule of Civil Procedure 12(b)(6) on the grounds that: (1) the complaint was barred under the Barton doctrine due to Harris’s failure to obtain approval of the bankruptcy court prior to filing suit in state court, and (2) each defendant was entitled to derived quasi-judicial immunity as a result of the entry of the June 30, 2003 order, which approved the sale of the assets.
While the motions to dismiss were pending, Harris amended his complaint and eliminated all claims for relief except the breach of contract claim, which remained exactly as it was in the original complaint.
The bankruptcy court dismissed the complaint with respect to each defendant. The court held that (1) Harris’s breach of contract claim was a core proceeding pursuant to 28 U.S.C. § 157(b)(2)(A), (N) and (O); (2) it had jurisdiction over the core proceeding pursuant to 28 U.S.C. § 1334; (3) Harris’s complaint had to be dismissed under the Barton doctrine because Harris had not sought leave of the bankruptcy court before suing in state court; and (4) Wittman, Swain and the Attorney defendants were entitled to derived quasi-judicial immunity because the bankruptcy court had originally approved all aspects of the sale of the property.
Harris appealed this decision to the United States District Court for the Southern District of California. The district court affirmed on the same grounds. This timely appeal followed.
II. Jurisdiction and Standard of Review
This is an appeal from a final order of the district court affirming the bankruptcy court’s grant of defendants’ motions to dismiss for failure to state a claim for relief. We have jurisdiction under 28 U.S.C. § 1291.
We review the district court’s acceptance of subject matter jurisdiction de novo, while reviewing any factual findings for clear error.
In re Harris Pine Mills,
III. Analysis
A. The bankruptcy court had subject matter jurisdiction to adjudicate Harris’s state law contract claim.
A bankruptcy court’s jurisdiction is established by statute. 28 U.S.C. § 1334(b) gives federal district courts subject matter jurisdiction over “all civil proceedings arising under title 11, or arising *737 in or related to cases under title 11.” 2 28 U.S.C. § 157(a) allows district courts to refer any of these proceedings to bankruptcy courts.
However, because bankruptcy judges are not Article III judges, the Constitution limits their ability to adjudicate— i.e., to render a final judgment — to issues that are at the “core” of the bankruptcy power. 3 Because of this limitation, 28 U.S.C. § 157(b)(1) provides bankruptcy judges authority to make binding decisions only in “core proceedings” 4 that arise under or arise in a case under Title 11. A bankruptcy judge may hear a non-core proceeding that is otherwise related to a case under Title 11, but there, the bankruptcy judge may make only proposed findings of fact and conclusions of law to the district judge, who reviews all non-core matters de novo. 28 U.S.C. § 157(c)(1).
1. Harris’s claim arose in his Chapter 7 bankruptcy case; therefore, the bankruptcy court could hear it.
“Arising under” and “arising in” jurisdiction are terms of art. “Congress used the phrase ‘arising under title 11’ to describe those proceedings that involve a cause of action created or determined by a statutory provision of title 11.”
Harris Pine Mills,
A civil proceeding “arises in” a Title 11 case when it is not created or determined by the bankruptcy code, but where it would have no existence outside of a bankruptcy case.
Harris Pine Mills,
In Harris Pine Mills, the plaintiff sued the bankruptcy trustee and the trustee’s agents in Oregon state court. Id. at 1434. The plaintiff alleged state law tort claims *738 consisting of fraud, negligence, and negligent misrepresentation surrounding the trustee’s sale of one of the estate assets the plaintiff unsuccessfully attempted to purchase. Id. The trustee removed the case to federal district court, and sought to have the case referred to the bankruptcy court. Id. Plaintiff objected and moved to remand the case back to state court. Id. The district court denied the motion to remand and determined that it had jurisdiction under § 1334(b) because the state law claims arose in the bankruptcy case. Id. We affirmed. 5 Id. at 1438.
Because the plaintiff sued the bankruptcy trustee for the trustee’s conduct in administering the bankruptcy estate, the state law claims arose in the bankruptcy case and were subject to federal jurisdiction. Id.
Here, although this is a state law cause of action, Harris’s claim arose in his bankruptcy case because it could not exist independently of his bankruptcy case. Harris alleged that Wittman, the bankruptcy trustee, breached the Settlement Agreement by selling bankruptcy estate assets that she had agreed not to sell, in exchange for Swain’s release of his claims against the estate and his assumption of other estate liabilities that Harris alleges were already released by the Settlement Agreement. Harris’s claim is similar to the state law tort claims in Hams Pine Mills. Therefore, Harris’s state law contract claim arose in his bankruptcy case, and it could be referred to the bankruptcy court.
2. This is a “core” bankruptcy proceeding; therefore, the bankruptcy court could make binding determinations.
Core proceedings are listed in the statute at 28 U.S.C. § 157(b)(2). They include but are not limited to: matters concerning the administration of the estate,
Id.
§ 157(b)(2)(A); orders approving the sale of property,
Id.
§ 157(b)(2)(N); and other proceedings affecting the liquidation of the assets of the estate,
Id.
§ 157(b)(2)(0). Subsections (A) and (0) are considered the “catchall” provisions, whereas subsections (B)-(N) are considered the more specific provisions.
In re Castlerock Properties,
As discussed above, we concluded in
Harris Pine Mills
that the plaintiffs state law tort claims against the trustee for the trustee’s conduct surrounding the sale of estate assets arose in the bankruptcy case.
The facts in Harris’s case are very similar to those in Harris Pine Mills. There, the plaintiff alleged the trustee’s sale of estate assets was fraudulent. Here, Harris alleges the trustee’s sale of estate assets was a breach of contract. Both causes of action arose from the trustee’s post-petition conduct pursuant to the trustee’s duty to administer the bankruptcy estate. Furthermore, because Swain paid for the assets in part by releasing his claims against the estate, and assuming the estate’s liability for the Attorney defendants’ attorneys’ fees, Swain’s and the Attorney defendants’ alleged breach of contract in “contriving” those claims was inextricably intertwined with the sale of estate assets. Under Harris Pine Mills, therefore, Harris’s proceeding is a core proceeding under § 157(b)(2)(A) because the breach of the Settlement Agreement was inextricably intertwined with the sale of estate assets' — -the literal administration of the bankruptcy estate.
Although
Harris Pine Mills
appears to be directly on point and provides for core jurisdiction, Harris contends that an older Ninth Circuit opinion,
Castlerock,
prevents the conclusion that core jurisdiction exists over a state contract claim where that claim qualifies as a core proceeding only under subsection (A) or (O). In
Castler-ock,
the state law contract action was already pending in state court when Castler-ock filed for bankruptcy; at that point, the claim was automatically stayed.
Harris contends this precludes core proceeding jurisdiction over his state law contract claim because the claim does not fall within one of the specific provisions of § 157(b)(2)(B)-(N). Harris is correct that core proceeding jurisdiction in his case exists only under the “catchall” provisions (A) and (0), not the specific provision (N), as discussed above. Thus, at first blush, it appears Harris’s state law contract claim should not be considered a core proceeding under Castlerock, despite the similarity to Harris Pine Mills.
However, at second blush, our holding in
Castlerock
is not as broad as Harris contends, and it certainly does not entirely eliminate subsections (A) and (0) of the statute from ever providing core proceeding jurisdiction to bankruptcy courts over state law contract claims. Rather, our main consideration to reach the holding in
Castlerock
was that “a court should avoid characterizing a proceeding as ‘core’ if to do so would raise constitutional problems.”
Id.
Thus, the court concluded the “catchall” provisions should be interpreted narrowly in light of the Supreme Court’s decision in
Marathon. Id.
Because exercising jurisdiction over the contract claim in
Castlerock
would have posed the same problem as the contract claim in
Marathon,
the
Castlerock
court was “persuaded” that the contract claim did not fall into either subsection (A) or (0) of § 157(b)(2), even if it
arguably
fell within a broad reading of those sections.
Id.
Thus, we held that state law contract claims that only
“arguably
fit within the literal wording of the two catchall provisions” should be considered non-core.
Id.
(emphasis added). Essentially,
Castlerock
holds that, under principles of constitutional avoidance, the otherwise broad “catchall” provisions of bankruptcy court core jurisdiction should be interpreted narrowly, not that there are
no circumstances
under which the “catchall” provisions can provide core jurisdiction.
Id.
at 162;
see In re Mankin,
Here,
Castlerock
does not apply. First, Harris’s state law contract claim does not
arguably
fall within § 157(b)(2)(A). Rather, our precedent compels the conclusion it
literally
falls within it. As the court in
Harris Pine Mills
noted, the sale of bankruptcy estate assets
is
an administrative activity of the bankruptcy trustee.
Furthermore, unlike in
Castlerock,
there is no potential Article III problem under the Supreme Court’s decision in
Marathon
*741
with the bankruptcy court’s exercise of jurisdiction over Harris’s post-petition contract claim. There was no majority opinion in
Marathon.
The plurality reasoned that private right suits, as opposed to public right suits, must be adjudicated by Article III courts, and that “Northern’s right to recover contract damages to augment its estate is one of private right.”
Marathon,
Although the Ninth Circuit has not yet addressed whether post-petition contract claims arising from the trustee’s sale of assets pass constitutional muster under
Marathon,
the First Circuit has held that they do.
See Arnold Print Works,
The First Circuit’s reasoning is equally applicable here. Harris’s contract claim is not a “traditional” contract action because the Settlement Agreement he claims was breached only came into being post-petition and was made with the trustee and Special Representative of the estate. Further, its terms directly related only to the administration of the bankruptcy estate. Harris’s claim is thus distinguishable from the suit at issue in Marathon, and there is no problem with a bankruptcy court exercising jurisdiction over it. Because there is no constitutional problem under Marathon, and because Harris’s contract suit more than “arguably” fits within subsection (A), Castlerock does not apply and core proceeding jurisdiction existed under our holding in Harris Pine Mills.
B. The district court erred when it dismissed Harris’s suit for lack of subject matter jurisdiction under the Barton doctrine.
The district court erred when it affirmed the bankruptcy court’s dismissal of Harris’s suit for lack of subject matter jurisdiction under the
Barton
doctrine, because the
Barton
doctrine is not a ground to dismiss a suit that is proceeding in the appointing bankruptcy court. As applied in the Ninth Circuit, the
Barton
doctrine requires “that a party must first obtain leave of the bankruptcy court before it initiates an action
in another forum
against a bankruptcy trustee or other officer appointed by the bankruptcy court for acts done in the officer’s official capacity.”
In re Crown Vantage, Inc.,
Here, it is undisputed that Harris did not seek leave of the appointing court before filing his claim in state court. As a result, when the case was removed to bankruptcy court, the bankruptcy court held that, under the Barton doctrine, even as the appointing court, it did not have subject matter jurisdiction to hear Harris’s claim, and so dismissed the suit.
This was error, however, because, absent leave of the appointing court, the Barton doctrine denies subject matter jurisdiction to all forums except the appointing court. The Barton doctrine is a practical tool to ensure that all lawsuits that could affect the administration of the bankruptcy estate proceed either in the bankruptcy court, or with the knowledge and approval of the bankruptcy court. The Barton doctrine is not a tool to punish the unwary by denying any forum to hear a claim when leave of the bankruptcy court is not sought. When Harris’s case was removed to the appointing bankruptcy court, all problems under the Barton doctrine vanished. Therefore, the district court erred in affirming the bankruptcy court’s dismissal of Harris’s suit for lack of subject matter jurisdiction under the Barton doctrine.
However, this error does not affect the result because we affirm on the alternate ground given by both the district court and the bankruptcy court, that is: All of the defendants are entitled to derived quasi-judicial immunity; therefore, Harris fails to state a claim upon which relief can be granted.
C. Appellees are entitled to derived quasi-judicial immunity.
The district court did not err when it held that Wittman, Swain, and the Attorney defendants were entitled to derived quasi-judicial immunity. “Bankruptcy trustees are entitled to broad immunity from suit when acting within the scope of their authority and pursuant to court order.”
Bennett v. Williams,
For derived quasi-judicial immunity to apply, the defendants must satisfy the following four elements: (1) their acts were within the scope of their authority; (2) the debtor had notice of their proposed acts; (3) they candidly disclosed their proposed acts to the bankruptcy court; and (4) the bankruptcy court approved their acts.
Bennett,
*743 1. Wittman is entitled to derived quasi-judicial immunity.
Harris alleged Wittman breached the Settlement Agreement when she agreed that Swain was entitled to be paid from the estate approximately $1 million in “contrived claims” that had already been released by the Settlement Agreement, and when she sold the assets to Swain in exchange for $125,000 cash and Swain’s release of those claims. These acts of Wittman meet all four elements for derived quasi-judicial immunity.
First, Wittman’s sale of the estate assets, as well as her determination that the consideration Swain was to pay for those assets was in the best interest of the estate, were within the scope of her statutorily conferred authority as trustee. 11 U.S.C. § 704(a)(1). Second, Wittman filed notice of the proposed sale, and served Harris with such notice, on May 2, 2003. Third, the notice fully set out the details of the proposed sale of the Alpine property and 1957 Mercedes-Benz to Jack Swain, including the consideration Swain was to pay. The notice explained that Wittman believed the sale was in the best interest of the estate, that Swain was releasing the estate from liability for all the fees and costs associated with his prosecution of the fraudulent conveyance proceeding in his role as Special Representative of the estate, including the attorneys’ fees of the Attorney defendants. The notice also provided a detailed accounting of the source of said fees and costs. Fourth, and finally, the bankruptcy court, after a hearing, approved the sale.
2. Swain and the Attorney Defendants are entitled to derived quasi-judicial immunity.
Harris alleged Swain and the Attorney defendants breached the Settlement Agreement because the approximately $1 million of estate liability — including the Attorney defendants’ attorneys’ fees from the fraudulent conveyance proceeding, Swain’s fees and costs from that proceeding, and Sandra Harris’s $218,000 lien against the Alpine property — that Swain was releasing or assuming in exchange for the estate assets had already been released by the terms of the settlement. Thus, Swain and the Attorney defendants were asserting rights to be paid from the estate, which Harris alleges they had agreed to release. However, Swain and the Attorney defendants, similarly to Witt-man, satisfy all four elements for derived quasi-judicial immunity.
First, their acts of making claims against the estate for their costs and fees associated with the fraudulent conveyance proceeding were within the scope of the authority conferred to them by the bankruptcy court. Under the Assignment Agreement, Swain was authorized to recover from the estate his costs of prosecuting the estate’s fraudulent conveyance proceeding against Harris and Mrs. Harris and 68% of the net recovery from that proceeding. The Attorney defendants were also authorized, under the Assignment Agreement, to recover their fees from the estate. The bankruptcy court specifically approved the Assignment Agreement and therefore authorized their recovery of fees and costs. Second, Harris had notice that Swain and the Attorney defendants were making these claims when Wittman served Harris with notice of the proposed sale on May 2, 2003, which notice included a detailed account of these claims. Third, the notice fully set out the claims Swain and the Attorney defendants had against the estate and the source of all of their claims. Fourth and finally, after a hearing, the bankruptcy court approved all of these claims, and Swain’s release or *744 assumption of those claims in exchange for the Alpine property.
Thus, all of the appellees are entitled to derived quasijudicial immunity.
AFFIRMED.
Notes
. The record does not establish whether Swain actually paid Mrs. Harris.
. Title 11 of the United States Code contains the entire bankruptcy code. This includes Chapter 7, Chapter 11, and Chapter 13 bankruptcy cases.
. See
Northern Pipeline Constr. Co. v. Marathon Pipe Line Co.,
.The statute provides a non-exclusive list of core proceedings at 28 U.S.C. § 157(b)(2)(A)-(P).
. As discussed
infra,
the court also determined that the state law claims were core bankruptcy proceedings.
Harris Pine Mills,
. In
Arnold Print Works,
the debtor — Arnold Print Works — filed for bankruptcy but continued to manage its property as a debtor-in-possession.
