concurring in the result:
The majority concludes that the Colorado Court of Appeals erred in determining that an agent’s signature purporting to be that of his principal was “unauthorized” under section 4-3-404(1), 2 C.R.S. (1992). Maj. op. at 1263, 1266. It therefore reverses the judgment of the court of appeals and remands the *1267case to that court for further proceedings. Maj. op. at 1266. Although I agree that the court of appeals erred, I conclude that it erred only by applying an incorrect test to determine whether a principal is precluded by negligence from defending against liability to a holder in due course. I would therefore reverse the judgment of the court of appeals and remand the case for resolution of the remaining issues on appeal and for further proceedings. Accordingly, I concur in the result reached by the majority.
I.
In 1982, Raymond C. Mayer (Mayer), who was president of Western Slope Investment & Development, Inc. (Western Slope), granted a general power of attorney to R. Martin Rhodes II (Rhodes), who was an officer of and attorney for Western Slope, for the purpose of conducting business for Mayer. Rhodes subsequently signed various documents for Mayer and Western Slope.1 In September 1988, Rhodes executed a $40,000 promissory note payable to Rhodes by Western Slope, together with a deed of trust on certain Western Slope property to secure payment of the note. The note and deed of trust contained only Mayer’s purported signature, which had been affixed by Rhodes. In both documents, Mayer was identified under the signature as the president of Western Slope, but neither document indicated that Rhodes had signed Mayer’s name. In fact, Rhodes notarized the deed of trust, attesting that Mayer had acknowledged the instrument.2 In October 1988, Rhodes assigned the note and deed of trust to Clarence E. Willey (Willey) as collateral for a $10,000 loan from Willey. After the promissory note for that loan became due and Willey was unable to collect on it, he instituted the present suit against Mayer,3 Western Slope, and Rhodes. The case was tried to the La Plata County District Court in January 1991.
Following the bench trial, the trial court found that Mayer had not authorized Rhodes to sign Mayer’s name to the $40,000 promissory note. The court also found that Willey was a holder in due course of that note. Under section 4-3-305(2), 2 C.R.S. (1992), a holder in due course takes an instrument free from all defenses of any party to the instrument with whom the holder has not dealt except for certain specified defenses, including “illegality of the transaction.” Mayer and Western Slope argued to the trial court that Mayer had not authorized Rhodes to sign Mayer’s name to the note, and that therefore neither Western Slope nor Mayer was “a party to the instrument” and the signing was an illegal transaction. Thus, argued Mayer and Western Slope, even if Willey was a holder in due course, Willey was not immune under section 4-3-305 from the defense that the signature was unauthorized.
The trial court ruled that Mayer had not authorized Rhodes to sign Mayer’s name to the note but that Mayer was precluded under sections 4-3-404, -406, 2 C.R.S. (1992),4 from *1268raising that defense. Mayer was so precluded because he did not expressly terminate Rhodes’ power of attorney and he allowed Rhodes to perform legal work for Western Slope. This conduct, said the court, constituted negligence. Furthermore, that negligence substantially contributed to the making of the note. Under section 4-3-406, 2 C.R.S. (1992), “[a]ny person who by his negligence substantially contributes to .... the making of an unauthorized signature is precluded from asserting the ... lack of authority against a holder in due course.... ” See also § 4-3-404(1), cmt. 4, 2 C.R.S. (1992) (providing that a person whose name is signed without authority may be precluded by negligence under section 4-3-406 from denying the signature). The court entered a judgment for Willey against Mayer and Western Slope in the amount of $5,000 plus interest and costs, and $5,000 in attorney fees.
II.
On appeal, the court of appeals did not reverse the trial court’s ruling that Mayer was negligent. Willey v. Mayer, 862 P.2d 959, 962 (Colo.App.1993). Instead, the court determined that .Mayer’s “alleged negligence” did not substantially contribute to the making of the unauthorized signature. Id. The court ruled that therefore Mayer was not precluded from asserting Rhodes’ lack of authority as a defense against liability to Willey under section 4-3-404(1).5 Id.
In reaching its determination that Mayer’s negligence did not substantially contribute to the making of the signature, the court of appeals referred to several cases from other jurisdictions. Id. The court adopted the interpretation of section 4-3-406 of the Uniform Commercial Code found in those cases. Id. That interpretation construes section 4-3-406 to require a causal connection or relationship between the negligence and the making of the unauthorized signature. Id.
Nevertheless, the court then analyzed the relationship not between Mayer’s negligence and the making of the signature but between Mayer’s negligence and Willey’s acceptance of the note. Id. This latter relationship is irrelevant to the requirement of section 4-3-406 that the negligence substantially contribute to the “making of an unauthorized signature.” It is also irrelevant to the interpretation of section 4-3-406 adopted by the court of appeals. The cases upon which the court relied for this interpretation themselves contain no requirement of a causal relationship between the negligence and the acceptance of an unauthorized signature by the holder in due course. Bagby v. Merill Lynch, Pierce, Fenner & Smith, Inc., 491 F.2d 192 (8th Cir.1974); J. Gordon Neely Enters., Inc. v. Am. Nat’l Bank, 403 So.2d 887 (Ala.1981); Gast v. Am. Casualty Co., 99 N.J.Super. 538, 240 A.2d 682 (1968); Gresham State Bank v. O and K Constr. Co., 231 Or. 106, 370 P.2d 726 (1962).
III.
The majority avoids the issue of Mayer’s negligence by finding that under the power of attorney, Rhodes had actual authority to sign Mayer’s name to the promissory note but that Rhodes had no authority to transfer the note to Willey. Maj. op. at 1265, 1266. The issue of negligence arises under sections 4-3-404 and -406 which pertain only to unauthorized signatures. §§ 4-3-404, -406, 2 C.R.S. (1992). Therefore, under the majority’s analysis, because Rhodes did not make an unauthorized signature, the issue of negligence does not arise. The majority then *1269analyzes Rhodes’ unauthorized transfer of the note under agency law, and concludes, apart from any consideration of negligence, that Mayer is liable to Willey because Willey is a holder in due course. Maj. op. at 1266.
I disagree with the majority’s conclusion that Rhodes had authority to sign Mayer’s name to the promissory note. I do agree that situations may arise, as the cases and treatise cited by the majority indicate, in which an agent cleai'ly has authority to sign a negotiable instrument but then acts without authority in pledging that instrument as security. Maj. op. at 1265-1266. This case, however, does not present such a situation.
The majority cites the Restatement (Second) of Agency (1957) (Restatement) to support the conclusion that Rhodes had authority to sign but no authority to transfer the note. Maj. op. at 11-12. However, analysis of the Restatement, including the sections quoted by the majority, indicates that Rhodes lacked authority to sign the note because he was acting with an improper purpose.
Under the Restatement, an agent has no authority to act other than for the benefit of the principal. Restatement §§33 cmt. a (agent has authority to do only what he reasonably believes the principal desires him to do), 39 cmt. a (agent has authority to act only for principal’s benefit), 76 cmt. c (agent has no authority to execute negotiable instruments for his own account); see also Restatement § 34 cmt. h (powers of attorney are interpreted in light of general customs and relations of the parties and all-embracing expressions such as “as sufficiently in all respects as we ourselves could do personally in the premises” are discounted or discarded).
The three sections of the Restatement quoted by the majority reiterate that an agent who acts contrary to the wishes of the principal is acting without authority because of that improper purpose. Maj. op. at 11-12. The three sections indicate that despite this lack of authority, the principal is liable to a holder in due course as if the agent acted with authority. Restatement §§76 cmt. c (even though agent lacks authority because of improper purpose, a bona fide purchaser in due course has rights against the principal “as if the agent’s act were authorized”), 165 cmt. d (even though agent lacks authority because acting with an improper purpose (see cmt. a), the principal is subject to liability to a holder in due course), 173 cmt. a (even though agent acts contrary to the principal’s directions, the principal is liable to a holder in due course “as if the instrument were authorized”).
The Restatement, therefore, does not support the majority’s conclusion that Rhodes acted with authority when signing Mayer’s name to the $40,000 promissory note made payable to himself. See also People v. Rhodes, 814 P.2d 787, 789 (Colo.1991) (attorney discipline case in which this court noted that Rhodes “admitted that he ... had signed Mayer’s name to [the promissory note and deed of trust] without authorization”).
IV.
Because Rhodes signed Mayer’s name to the promissory note for an improper purpose, I conclude, as did the trial court, that Mayer did not authorize Rhodes to sign Mayer’s name on the promissory note. Under agency law, as indicated by the previous discussion of the Restatement, Mayer would nevertheless be liable on the note to Willey because Willey is a holder in due course. However, under the Uniform Commercial Code, Mayer might escape liability if he is not precluded by negligence from asserting Rhodes’ lack of authority. §§ 4-3-305(2)(b), -404(1), 2 C.R.S. (1992). In resolv■ing this tension between the Restatement and- our statutes, our statutes must control.
In the present case, however, it is not necessary to resolve the tension because the trial court found on adequate evidence that Mayer was negligent and that his negligence substantially contributed to the making of the promissory note. As discussed above, the court of appeals applied the wrong test to determine whether, under section 4-3-406, 2 *1270C.R.S. (1992), Mayer’s negligence substantially contributed to the making of the unauthorized signature. The court of appeals therefore erred in reversing the trial court’s judgment. Because Mayer’s negligence substantially contributed to Rhodes’ signing of the note, Mayer is precluded from asserting Rhodes’ lack of authority against Willey. § 4-3-406, 2 C.R.S. (1992). Therefore, just as under the Restatevient, Mayer is liable to Willey because Willey is a holder in due course. ■§ 4-3-305, 2 C.R.S. (1992).
V.
For the foregoing reasons, I would reverse the judgment of the court of appeals and remand the case to that court for resolution of the remaining issues on appeal and for further proceedings. Accordingly, I concur in the result reached by the majority.
. The general power of attorney was given by Mayer individually. Rhodes, however, purported to act as attorney-in-fact for Mayer in Mayer’s capacity as president of Western Slope as well as in Mayer's individual capacity. No issue is presented on certiorari review concerning whether Rhodes had authority to act for Western Slope in this manner. I will assume, therefore, that Rhodes was authorized to act for Mayer as president of Western Slope to the same extent that he was authorized to act for Mayer individually.
. Willey did not rely on the power of attorney, or know that Rhodes had Mayer’s power of attorney. Rhodes testified that he attempted to duplicate or forge Mayer's signature on the $40,000 note and admitted that as a notary he falsely stated that Mayer appeared before him and acknowledged his signature on the deed of trust. A notary cannot notarize a document in which he is a payee. § 12-55-110(2), 5B C.R.S. (1991); See also Brereton v. Bennett, 15 Colo. 254, 25 P. 310 (1890).
. Western Slope was alleged to be Mayer’s alter ego as a basis for the claim against Mayer.
. § 4-3-404, 2 C.R.S. (1992), provides:
Any unauthorized signature is wholly inoperative as that of the person whose name is signed unless he ratifies it or is precluded from denying it....
§ 4-3-406, 2 C.R.S. (1992), provides:
Any person who by his negligence substantially contributes to ... the making of an unauthorized signature is precluded from asserting *1268the ... lack of authority against a holder in due course....
. The majority concludes that the issue of whether Mayer's negligence substantially contributed to the making of the unauthorized signature is not properly before us. Maj. op. at 1263 n. 6. We granted certiorari on the following issue:
Whether the court of appeals erred in finding that a holder in due course of a promissory note, signed on behalf of the principal by his agent who was vested with the power of attorney, could not sue upon the note and enforce it against the principal.
Nothing in this language precludes us from a proper analysis and disposition of the case.