Mutual Mistake argument in contract dispute to avoid enforcement or liability

   
Mutual Mistake as affirmative defense in contract dispute

To establish the defense of mutual mistake in a written instrument, [Defendant] must plead and prove (1) the original agreement, and (2) a mutual mistake made in reducing the original agreement to writing. Peters v. Gifford-Hill & Co., 794 S.W.2d 856, 860 (Tex. App.-Dallas 1990, writ denied). 
   
The party asserting mutual mistake must prove what the true agreement was, but "his case is not made by proof that there was an agreement which is at variance with the writing. He must go further and establish the fact that the terms and provisions of the writing which differ from the true agreement made were placed in the instrument by mutual mistake." Id. (citing Sun Oil Co. v. Bennett, 84 S.W.2d 447, 451 (Tex. 1935)); see also Balboa Ins. Co. v. K&D & Assoc., 589 S.W.2d 752, 757 (Tex. Civ. App.-Dallas 1979, writ ref'd n.r.e.) (evidence must show both parties were acting under the same misunderstanding of the same material fact to establish mutual mistake). 
  
Mutual mistake is generally established from all of the facts and circumstances surrounding the parties, and the execution of the instrument. Simpson v. Curtis, 351 S.W.3d 374, 378 (Tex. App.-Tyler 2010, no pet.).

SOURCE:  DALLAS COURT OF APPEALS -  No. 05-11-01536-CV - 6/7/2013 

Mutual mistake as a defense – unilateral mistake likely won’t work, not to mention second thoughts about signing the contract

THE ELEMENTS OF MUTUAL MISTAKE AS A DEFENSE

The defense is not available to undo a contract upon second thoughts about the wisdom of signing it, or after-the-fact regrets by one party.

The elements of mutual mistake are: (1) a mistake of fact; (2) held mutually by the parties; (3) which materially affects the agreed-on exchange. City of The Colony v. N. Tex. Mun. Water Dist., 272 S.W.3d 699, 735 (Tex. App.-Fort Worth 2008, pet. dism'd).

A mutual mistake of fact occurs when the parties to an agreement have a common intention, but the written agreement does not accurately reflect that intention due to a mutual mistake. See Smith-Gilbard v. Perry, 332 S.W.3d 709, 713 (Tex. App.-Dallas 2011, no pet.); City of The Colony, 272 S.W.3d at 735. When mutual mistake is alleged, the party seeking relief must show what the parties' true agreement was and that the instrument incorrectly reflects that agreement because of a mutual mistake. Atlantic Lloyds Ins. Co. v. Butler, 137 S.W.3d 199, 213 (Tex. App.-Houston [1st Dist.] 2004 pet. denied). Under the doctrine of mutual mistake, when parties to an agreement have contracted under a misconception or ignorance of a material fact, the agreement will be voided. Walden v. Affiliated Computer Servs., Inc., 97 S.W.3d 303, 326 (Tex. App.-Houston [14th Dist.] 2003, pet. denied).

To prove a mutual mistake, the evidence must show that both parties were acting under the same misunderstanding of the same material fact. Id. A unilateral mistake by one party, combined with knowledge of that mistake by the other party, is equivalent to mutual mistake. Davis v. Grammer, 750 S.W.2d 766, 768 (Tex. 1988). But, "[a] mistake by only one party to an agreement, not known or induced by acts of the other party[,] will not constitute grounds for relief." Smith-Gilbard, 332 S.W.3d at 713-14 (quoting Johnson v. Snell, 504 S.W.2d 397, 399 (Tex. 1974)).

Mutual mistake should not be available to avoid the results of an unhappy bargain. Williams v. Glash, 789 S.W.2d 261, 265 (Tex. 1990). Parties should be able to rely on the finality of freely bargained agreements. Id.

SOURCE: HOUSTON COURT OF APPEALS - No. 01-11-01034-CV – 2/21/2013

Mutual Mistake as a Contract Defense

AVOIDANCE OF CONTRACT BASED ON MUTUAL MISTAKE When parties to an agreement have contracted under a misconception or ignorance of a material fact, the agreement will be avoided under the doctrine of mutual mistake. Williams v. Glash, 789 S.W.2d 261, 264 (Tex. 1990). When can the affirmative defense of mutual mistake be invoked? To prove a mutual mistake, the evidence must show that both parties were acting under the same misunderstanding of the same material fact when the agreement was executed. Seymour v. American Engine & Grinding Co., 956 S.W.2d 49, 58 (Tex. App.—Houston [14th Dist.] 1996, writ denied). “The doctrine of mutual mistake must not routinely be available to avoid the results of an unhappy bargain.” Williams v. Glash, 789 S.W.2d 261, 265 (Tex. 1990). SOURCE: 04-08-00745-CV (9/9/09) (San Antonio Court of Appeals) (defense of mutual mistake not conclusively established)