This appeal arises from a dispute between Castex Energy and MC Asset Recovery (“MCAR”) regarding the alleged *587 breach of a purchase and sale agreement. Castex appeals the district court’s denial of its motion to compel arbitration. For the following reasons, we AFFIRM.
I.
In 2001, Mirant Corporation and its affiliates (collectively, “the Mirant Entities”), MCAR’s predecessors in interest, purchased interests in Louisiana mineral properties and obtained a 75% majority interest in a closely held corporation pursuant to a 2001 Purchase and Sale Agreement (“PSA”) with Castex (hereinafter “the Assets”). In 2002, the Mirant Entities agreed to sell the Assets back to Cas-tex pursuant to another PSA. After the closing of the 2002 PSA, Castex sold the Assets to Apache Corporation. The Mir-ant Entities alleged breach of the 2002 PSA and fraud, claiming Castex should have disclosed the fact that it was negotiating with Apache for a sale of the Assets.
This lawsuit originated as a fraudulent transfer adversary proceeding initiated by some of the Mirant Entities in connection with Mirant Corporation’s bankruptcy. The original complaint sought to avoid the 2001 PSA and the 2002 PSA as constructively fraudulent transfers, but did not allege breach of the 2002 PSA. Two days after filing their original complaint, the Mirant Entities moved to stay the adversary proceeding. The bankruptcy court granted the request and stayed the case for 19 months, until January 2007.
Once the stay expired, Castex filed its answer to the original complaint. By that time, MCAR had been designated as the assignee of the claims raised in the original complaint and successor in interest to the Mirant Entities. Castex’s answer contained several affirmative defenses, including its right to compel arbitration. Castex then requested a jury trial before the district court, and, on that basis, moved to withdraw the reference to the bankruptcy court. Castex stated its intention to preserve its right to compel arbitration in a footnote in the motion to withdraw reference to the bankruptcy court, but it did not move to compel arbitration at that time. The district court granted the motion to withdraw reference to the bankruptcy court.
After Castex answered, MCAR filed its first amended complaint and largely abandoned its original grounds for relief and raised state law claims arising from the 2002 PSA for breach of contract, fraud, violations of the Texas Blue Sky Law, and breach of fiduciary duty. Castex did not move to compel arbitration at that time. Instead, it filed a motion to dismiss under Fed.R.Civ.P. 9(b), 12(b)(6), and 12(c), arguing that MCAR’s complaint was deficient because it failed to allege sufficient facts to state a claim for relief. In a footnote in the motion, Castex reserved its right to compel arbitration.
After filing its motion to dismiss, Castex filed a motion for a protective order, seeking to stay discovery in the case, pending the district court’s resolution of its motion to dismiss. Castex also filed a motion for relief from the court’s initial scheduling order, seeking relief from the requirement that the parties make initial disclosures pursuant to Fed.R.Civ.P. 26. The district court entered a protective order staying all discovery in the case pending the outcome of the motion to dismiss. MCAR later moved for limited relief from the protective order in order to depose an employee of the Mirant Entities who was scheduled to leave his position. Castex objected to this motion and the district court denied it.
Before the district court ruled on the first motion to dismiss, MCAR filed its second amended complaint. This complaint contained modified versions of the *588 claims in the first amended complaint and added claims for fraud, fraudulent inducement, and statutory fraud under Tex. Bus. & Com.Code § 27.01. In response to the second amended complaint, Castex filed a second motion to dismiss under Fed. R.Civ.P. 9(b), 12(b)(6), and 12(c). Once again, Castex reserved its right to compel arbitration in a footnote but did not move to compel arbitration. Castex also filed a separate motion to dismiss under Rule 12(b)(1) arguing that MCAR lacked standing because it had not been assigned any claims outside of the bankruptcy avoidance claims contained in the original complaint.
MCAR then filed a third amended complaint, which contained the same substantive causes of actions as the previous complaint but with more details added. Castex filed a third motion to dismiss pursuant to Rules 9(b) and 12(b)(6). As it had done in its previous motions to dismiss, Castex reserved its right to compel arbitration in a footnote. In its third motion to dismiss, Castex asked the district court to use its discretion to deny further amendments to MCAR’s complaint and asked that the court dismiss all claims with prejudice. On September 22, 2008, the district court partially granted the motion, dismissing Count VI (breach of fiduciary duty) with prejudice. The court denied the motion as to the remaining claims.
On October 6, 2008, Castex filed a motion to compel arbitration before answering the third amended complaint. MCAR responded to Castex’s motion to compel arbitration by arguing that Castex had waived that right by substantially invoking the judicial process. MCAR also claimed it had been prejudiced by incurring $265,559 in attorneys’ fees and costs in defending against the motions to dismiss. The district court denied the motion to compel arbitration. The district court noted that “[tjhere does not appear to be any dispute in this case over the existence or validity of the [arbitration clause] or whether [MCAR’s claims] fall within the scope of the [arbitration clause].” The district court, however, held that Castex had waived its right to compel arbitration because it had substantially invoked the judicial process by filing multiple motions to dismiss, seeking and partially obtaining a dismissal with prejudice, and waiting eighteen months before invoking arbitration. It also found that MCAR suffered prejudice through delay, legal fees, and the dismissal of its claim for breach of fiduciary duty.
II.
We have jurisdiction of this appeal even though the district court’s denial of Castex’s motion to compel arbitration is an interlocutory order.
Nicholas v. KBR, Inc.,
*589 A.
We first examine whether Castex substantially invoked the judicial process. To invoke the judicial process, a “party must, at the very least, engage in some overt act in court that evinces a desire to resolve the arbitrable dispute through litigation rather than arbitration.”
Subway Equip. Leasing Corp. v. Forte,
“A party waives arbitration by seeking a decision on the merits before attempting to arbitrate.”
Petroleum Pipe Ams. Corp. v. Jindal Saw, Ltd.,
Moreover, in its third motion to dismiss, Castex sought the dismissal of MCAR’s complaint with prejudice. As the district court observed, “[a] dismissal with prejudice for failure to state a claim is a decision on the merits and essentially ends the plaintiffs lawsuit.”
Mahone v. Addicks Util. Dist. of Harris County,
We also note that Castex did not initially present its motion to compel arbitration to the district court as an alternative to its motion to dismiss. Rather, Castex first sought “a decision on the merits before attempting to arbitrate.”
Petroleum Pipe,
Castex, however, moved to compel arbitration only after the district court had partially denied its third motion to dismiss, despite being fully aware of its right to compel arbitration from the outset.
2
We are not convinced that “[Castex], having learned that the district court was not receptive to its arguments, should be allowed a second bite at the apple through arbitration.”
Petroleum Pipe,
Taking all these factors into consideration, we conclude that Castex sought a
*591
decision on the merits before the district court. We agree with the district court that Castex “substantially invoked the judicial process” through its actions.
Walker,
B.
“In addition to invocation of the judicial process, the party opposing arbitration must demonstrate prejudice before we will find a waiver of the right to arbitrate.”
Nicholas,
We first address the question of whether Castex made a timely demand for arbitration. “While the mere failure to assert the right to demand arbitration does not alone translate into a waiver of that right, such failure does bear on the question of prejudice.”
Republic Ins. Co.,
We now turn to the district court’s findings. Castex argues that it did not force MCAR to incur any litigation expenses. The district court, however, found that MCAR had spent over $260,000 in legal fees that were solely attributed to defending against Castex’s discovery motions and motions to dismiss. Having thoroughly reviewed the record, we cannot say that this finding was clearly erroneous. MCAR incurred considerable legal expenses as a result of Castex’s use of the federal court system. Such expenses support a finding of prejudice.
In addition to litigation expenses, the district court found that MCAR had suffered prejudice to its legal position as a result of Castex’s motions to dismiss and motions to stay discovery. Castex cites to the Second Circuit’s decision in
Sweater Bee by Banff, Ltd. v. Manhattan Indus., Inc.,
[i]n such a case, a motion to dismiss may not be inconsistent with a right to arbitrate; it might be necessary for the defendant to file the motion both to sort out the claims before it can intelligently decide whether to arbitrate and to protect its rights in court if the arguably non-arbitrable claims do turn out to be non-arbitrable.
*592
St. Mary’s Med. Ctr. of Evansville, Inc. v. Disco Aluminum Prods. Co.,
Finally, the district court found that the eighteen-month delay between the filing of Castex’s original answer and its motion to compel arbitration wasted judicial resources and disadvantaged MCAR. We agree. As we stated in
Walker,
We agree with the district court that MCAR has demonstrated sufficient prejudice. Castex’s delay in seeking to compel arbitration forced MCAR to incur significant legal expenses, placed it in a weaker legal position, and delayed the resolution of this case for over eighteen months. Consequently, Castex has waived its right to compel arbitration.
For the foregoing reasons, the judgment of the district court is hereby AFFIRMED.
Notes
. Castex relies on
Gulf Guaranty Life Insurance Co. v. Connecticut General Life Insurance, Co.,
.
Castex argues that in
Williams v. Cigna Financial Advisors, Inc.,
. We likewise disapproved of a similar attempt to obtain a decision on the merits before moving for arbitration in Price v.
Drexel Burnham Lambert, Inc.,
. The D.C. Circuit recently expressed similar concerns regarding the potential for abuse of the judicial process through strategic use of a party’s right to compel arbitration.
See Khan v. Parsons Global Servs., Ltd.,
. We pause to note that Castex’s delay also forced the district court to rule on a detailed motion to dismiss, enter an order staying discovery, rule on Castex's motion for relief from the initial scheduling order, and rule on MCAR’s motion for relief from the protective order. While considerations of judicial economy do not factor into our prejudice analysis, we do not condone litigation tactics that result in the unnecessary outlay of substantial judicial resources.
