delivered the opinion of the Court.
The decision under review is that, although, at the time of removal' of a cause from a state court, the complaint disclosed an amount in controversy requisite to the federal court’s jurisdiction, a subsequent amendment, reducing the sum claimed to substantially less than that amount, necessitates remand to the state court. We granted the writ of certiorari because of alleged conflict with our decisions and with those of other federal courts.
The respondent, a corporation of Indiana, issued a summons out of the Superior Court of Marion County, Indiana, against the petitioner, a Minnesota corporation doing business in Indiana, and one Harlan as its agent. The complaint alleged that the respondent was subject to' the provisions of the Indiana Workmen’s Compensation Act and had entered into a contract of insurance with the petitioner, evidenced by a binder, whereby the petitioner insured the respondent against loss or expense by reason of claims for compensation for a period of thirty days from December 30, 1933, and agreed to act for the respondent in the filing of reports and notices under the Act; that, during the term of the insurance, employes of the respondent had suffered injury in the course of employment and made claims therefor; that the petitioner had been notified of each injury and investigated it in connection with the claim for compensation; that after the expiration of the contract the petitioner notified the respondent that it would not recognize any of the claims and denied liability under the binder; that as a consequence respondent was compelled to employ attorneys, investigators, and medical assistants to investigate and satisfy claims covered by the contract and to pay employes who had suffered injuries during the contract period, and *285 to pay, or obligate itself to pay, for medical, hospital, or dental bills in connection with such injuries; to the damage of the respondent in the sum of $4,000. It was alleged that the petitioner had acted, in making the contract, through Harlan, its authorized agent and representative, and an order was prayed that Harlan retain all moneys due by him to the petitioner for the purpose of answering -any judgment which might be recovered. The complaint concluded by demanding $4,000 and other appropriate relief. Upon the petitioner’s timely application the cause was removed to the United States District Court for Southern Indiana. The respondent thereafter filed an amended complaint, the substance of which is not now material, and later a “second amended complaint for breach of contract and for damages,” in which the allegations of the original complaint were repeated and damages were claimed in the sum of $4,000. An exhibit was attached which gave the names of the employes and the amounts expended in connection with their asserted injuries totaling $1,380.89. The court dismissed Harlan as a defendant, transferred the cause to the law docket, and overruled a demurrer to the complaint as not stating facts sufficient to constitute a cause of action. The answer denied the making of the contract. A jury trial was waived and the court made findings, stated its conclusions, and entered judgment for the respondent for $1,162.98. The petitioner appealed. The Court of Appeals refused to decide the merits on the ground that as the record showed respondent’s claim did not equal the amount necessary to give the District Court jurisdiction, the case should have been remanded to the state court. 1
The question presented is one of statutory construction. The act defining the jurisdiction of district courts of the *286 United States is § 24 of the Judicial Code. 2 So far as here material, the Code confers jurisdiction of a suit of a civil nature, where the matter in controversy exceeds, exclusive of interest and costs, the sum or value of $3,000 and is between citizens of different states.
Authority for removal of certain causes from a state to a federal court was first given by § 12 of the Judiciary Act of 1789 3 which permitted removal of a civil suit, instituted by a citizen of the state in which the suit was brought, against a citizen of another state, where the matter in dispute exceeded the sum or value of $500, exclusive of costs. Such removal could be had only at the instance of the nonresident defendant. The Act of July 27, 1866, 4 enlarged the privilege of removal by providing that if, in such a civil suit, it was shown that a nonresident defendant was party to a separable controversy, which could be determined without the presence of other defendants, that defendant might remove the cause.
The Judiciary Act of 1875 5 altered preexisting law to permit suits involving a controversy between citizens of different states to be removed by either party. The Judiciary Acts of 1887-1888 6 increased the jurisdictional amount to more than $2,000, exclusive of interest and costs, and confined the right of removal to a nonresident defendant, and the Judicial Code increased the limit to over $3,000, exclusive of interest and costs, and also restricted the privilege to nonresident defendants. 7 The *287 statute governing dismissal or remand for want of jurisdiction is § 37 of the Code. 8
“If in any suit commenced in a district court, or removed from a State court to a district court of the United States, it shall appear to the satisfaction of the said district court, at any time after such suit has been brought or removed thereto, that such suit does not really and substantially involve a dispute or controversy properly within the jurisdiction of said district court, or that the parties to said suit have been improperly or collusively made or joined, either as plaintiffs or defendants, for the purpose of creating a case cognizable or removable under this chapter, the said district court shall proceed no further therein, but shall dismiss the suit or remand it to the court from which it was removed, as justice may require, and shall make such order as to costs as shall be just.
This provision first appeared as § 5 9 of the Act of March 3, 1875 (supra), and save for the elision of a concluding clause, and the substitution of “district court” for “circuit court,” is identical with that section. It was included in the Judiciary Acts of 1887-1888, supra, and has been continuously in force since 1875. It altered the practice by requiring the court to dismiss or remand of its own motion in a proper case although want of jurisdiction was not raised by appropriate motion or by plea or answer, 10 but did not change the substantial basis for *288 the court’s action. The principles governing dismissal of a cause initiated in the federal court or the remand of one begun in a state court have remained as they were before the section was adopted.
The intent of Congress drastically to restrict federal jurisdiction in controversies between citizens of different states has always been rigorously enforced by the courts. The rule governing dismissal for want of jurisdiction in cases brought in the federal court is that, unless the law gives a different rule, the sum claimed by the plaintiff controls 11 if the claim is apparently made in good faith. 12 *289 It must appear to a legal certainty that the claim is really for less than the jurisdictional amount to justify dismissal. 13 The inability of plaintiff to recover an amount adequate to give the court jurisdiction does not show his bad faith or oust the jurisdiction. 14 Nor does the fact that the complaint discloses the existence of a valid defense to the claim. 15 But if, from the face of the pleadings, it is apparent, to a legal certainty, that the plaintiff cannot recover the amount claimed, or if, from the proofs, the court is satisfied to a like certainty that the plaintiff never was entitled to recover that amount, and that his claim was therefore colorable for the purpose of conferring jurisdiction, the suit will be dismissed. 16 Events oc *290 curring subsequent to the institution of suit which reduce the amount recoverable below the statutory limit do not oust jurisdiction. 17
What already has been said, and circumstances later to be discussed, lead to the conclusion that a dismissal would not have been justified had the suit been brought in the federal court. The principles which govern remand of a removed cause, more urgently require that it should not have been remanded. In a cause instituted in the federal court the plaintiff chooses his forum. He knows or should know whether his claim is within the statutory requirement as to amount. His good faith in choosing the federal forum is open to challenge not only by resort to the face of his complaint, but by the facts disclosed at trial, and if from either source it is clear that his claim never could have amounted to the sum necessary to give jurisdiction there is no injustice in dismissing the suit. Indeed, this is the court’s duty under the Act of 1875. In such original actions it may also well be that plaintiff and defendant have colluded to confer jurisdiction by the method of the one claiming a fictitious amount and the other failing to deny the veracity of the averment of amount in controversy. Upon disclosure of that state of facts the court should dismiss.
A different situation1 is presented in the case of a suit instituted in a state court and thence removed. There is a strong presumption that the plaintiff has not claimed a large amount in order to confer jurisdiction on a federal court or that the parties have colluded to that end. 18 *291 For if such were the purpose suit would not have been instituted in the first instance in the state but in the federal court. It is highly unlildy that the parties would pursue this roundabout and troublesome method to get into the federal court by removal when by the same device the suit could be instituted in that court. 19 Moreover, the status of the case as disclosed by the plaintiff’s complaint is controlling in the case of a removal, since the defendant must file his petition before the time for answer or forever lose his right to remove. 20 Of course, *292 if, upon the face of the complaint, it is obvious that the suit cannot involve the necessary amount, removal will be futile and remand will follow. 21 But the fact that it appears from the face of the complaint that the defendant has a valid defense, if asserted, to all or a portion of the claim, or the circumstance that the rulings of the district court after removal reduce the amount recoverable below the jurisdictional requirement, 22 will not justify remand. And though, as here, the plaintiff after removal, by stipulation, by affidavit, or by amendment of his pleadings, reduces the claim below the requisite amount, this does not deprive the district court of jurisdiction. 23
*293
Thus events occurring subsequent to removal which reduce the amount recoverable, whether beyond the plaintiff's control or the result of his volition, do not oust the district court's jurisdiction’ once it has attached.
24
This is well illustrated by
Kirby
v.
American Soda Fountain Co.,
Fifty years earlier in
Kanouse
v.
Martin,
We think this well established rule is supported by ample reason. If the plaintiff could, no matter how bona fide his original claim in the state court, reduce the amount of his demand to defeat federal jurisdiction the defendant’s supposed statutory right of removal would be subject to the plaintiff’s caprice. The claim, whether well or ill founded in fact, fixes the right of the defendant to remove, and the plaintiff ought not to be able to defeat that right and bring the cause back to the state court at his election. If he does not desire to try his case in the federal court he may resort to the expedient of suing for less than the jurisdictional amount, and though he would be justly entitled to more, the defendant cannot remove. 25
This view is further supported by the authorities as to causes in which jurisdiction depends on diversity of citizénship. It uniformly has been held that in a suit properly begun in the federal court the.change of citizenship of a party does not oust the jurisdiction. 26 The same *295 rule governs a suit originally brought in a state court and removed to a federal court. 27
The decisions as to remand of a cause removed because it involves a separable controversy are not inconsistent with those concerning remand for lack of jurisdictional amount. In the case of a separable controversy, if, after removal, the plaintiff discontinues or dismisses as to the defendant who removed, so that there no longer exists any separable controversy, the cause must be remanded. 28 If a cause be removed on this ground the whole case, including the controversy between citizens of the same state, is taken over by the federal court only because one or more of the defendants is entitled to invoke its jurisdiction. The basis of federal jurisdiction failing, it is proper that the remaining parties, who were involuntarily taken into the federal court, should, upon the cessation of the separable controversy which was the cause of their transmission to another tribunal, have their case returned to the state court.
The present case well illustrates the propriety of the rule that subsequent reduction of the amount claimed cannot oust the district court’s jurisdiction. Suit was instituted in the state court June 5, 1934. The lump sum claimed was largely in excess of $3,000, exclusive of interest and costs. The items which went to make up the respondent’s demand for indemnity were numerous and *296 each, in turn, was itself the total of several items of expenditure or liability. There is nothing to indicate that all of the sums for which reimbursement was claimed had actually been expended prior to the beginning of suit or that the sums thereafter to be expended had been ascertained. Not until the second amended complaint was filed in the United States court, in November 1934, did the respondent furnish a statement of the particulars of its claim. That statement is not inconsistent with the making of a claim in good faith for1 over $3,000 when the suit was instituted. Nor is there evidence that the petitioner when it removed the cause knew, or had reason to believe, that the respondent’s claim, whether well or ill founded in law or fact, involved less than $3,000. On the face of the pleadings petitioner was entitled to invoke the jurisdiction of the federal court, and a reduction of the amount claimed, after removal, did not take away that privilege.
The judgment is reversed and the cause is remanded to the Circuit Court of Appeals for further proceedings in conformity to this opinion.
Reversed.
Notes
90 F. (2d) 229.
Act of March 3, 1911, c. 231, § 24, as amended, 36 Stat. 1091, U. S. C. Tit. 28, § 41.
Act of Sept. 24, 1789, § 12, 1 Stat. 73, 79.
c. 288, 14 Stat. 306.
Act of March 3, 1875, 18 Stat. 470.
Act of March 3, 1887, § 1, 24 Stat. 552; Act of Aug. 13, 1888, § 1, 25 Stat. 433.
Act of March 3, 1911, e. 231, §§ 24 and 28, 36 Stat. 1087, 109.1, 1094.
Act of March 3, 1911, c. 231, § 37, 36 Stat. 1098, U. S. C. Tit, 28, § 80.
18 Stat. 472.
Prior to 1875 the courts did not act of their own motion but upon a motion to dismiss or a plea in abatement.
Smith
v.
Kernochen,
Wilson
v.
Daniel,
Peeler
v.
Lathrop,
Barry
v.
Edmunds, supra; Wetmore
v.
Rymer,
Smithers
v.
Smith,
Interstate Bldg. & L. Assn.
v.
Edgefield Hotel Co.,
Williams
v.
Nottawa, supra; Barry
v.
Edmunds, supra; Vance
v.
W. A. Vandercook Co.,
Mutual Life Ins. Co.
v.
Rose,
In
Smith
v.
Greenhow,
Hayward
v.
Nordberg Mfg. Co.,
Gordon
v.
Longest,
North American T. & T. Co.
v.
Morrison,
Levinski
v.
Middlesex Banking Co.,
Kanouse
v.
Martin, supra; Kirby
v.
American Soda Fountain Co.,
The same principle applies in cases where a fixed amount is requisite to jurisdiction on appeal.
Lee v. Watson,
Woods
v.
Massachusetts Protective Assn.,
34 F. (2d) 501. And an amendment in the state court reducing the claim below the jurisdictional amount before removal is perfected is effective to invalidate removal and requires a remand of the cause:
Maine
v.
Gilman,
Morgan’s Heirs
v.
Morgan,
Haracovic
v.
Standard Oil Co.,
Texas Transportation Co.
v.
Seeligson,
