Shawmut Worcester County Bank, N.A. (bank), the secured party, brought this action to recover a deficiency judgment from the defendants, guarantors of three promissory notes, after the primary debtor defaulted on the notes and after the bank sold the collateral at a private sale. In their answer the defendants raised the defense that the bank handled and disposed of the collateral in a manner that was not commercially reasonable. A judge in the Superior Court entered summary judgment for the bank, see Mass. R. Civ. P. 56,
We summarize the facts from the affidavits submitted by each party on the motion for summary judgment. On September 16, 1982, Rim Plastics, Inc. (Rim), a Massachusetts corporation with places of business in Upton and the Jamaica Plain section of Boston, Massachusetts, executed and delivered to the bank, ar national banking association, three promissory notes in the original principal amounts of $214,113.58, $48,726.16, and $100,000, respectively. The notes were secured by a security interest in machinery, equipment, accounts receivable, inventory, and other personal property of Rim. Also on September 16, 1982, David Miller, Edwin B. Carton, *275 and Judah Graulich 3 guaranteed to the bank the payment of all three notes, as well as other obligations of Rim. On August 24, 1983, at which time Rim was in default on its obligations to the bank pursuant to the notes, the bank demanded payment from the three guarantors. The guarantors have not paid any amount to the bank. After the default of Rim, and the defendants’ failure to pay the debt, the bank notified the defendants of its intention, as secured party, to take possession of, and to sell at auction, Rim’s collateral securing the note. In late November and early December, 1983, in preparation for a sale of the collateral, the bank engaged the services of a professional appraiser who appraised Rim’s equipment securing the notes at $57,116. Subsequently, the secured equipment at the Upton facility was moved to Rim’s Jamaica Plain location. The sale was advertised in the press and notices were sent to potential bidders in New England, New York, and New Jersey. On January 25, 1984, an auction sale of the equipment was conducted at Jamaica Plain, where $12,407.50 was realized. The collateral not sold at auction was later sold at a private sale for $40,000. Thus, the gross proceeds realized from the sale of the collateral were $52,407.50, or approximately ninety-two per cent of the appraised value of the collateral. The bank then filed suit for a deficiency judgment against the guarantors.
The guarantors, in the virtually identical affidavits submitted in opposition to the bank’s motion for summary judgment, attested to certain defects in the manner of handling and disposition of the collateral, which they also raise on appeal. The guarantors assert that the equipment sold by the bank was moved improperly to the auction site, resulting in the loss of some equipment and damage to other equipment. According to the guarantors’ affidavits, the equipment was moved from a well-lit modem molding plant in which the equipment was installed properly and in good working order, to an old warehouse. The warehouse, the guarantors assert, was unable to accommodate the equipment and, as a result, the equipment *276 was left unassembled and merely placed on the floor in a fashion unrelated to the use of the equipment in the injection molding process. The guarantors assert that some of the equipment was left outside in the rain after it was moved to Jamaica Plain and that a part of the equipment was permitted to roll down an embankment, rendering it useless and destroying the continuity of the equipment ultimately auctioned. Additionally, the guarantors state that certain chemicals were stored improperly, rendering the chemicals worthless. The bank’s ill-advised decision to move the equipment, the guarantors assert, caused the bank to incur $27,281.38 in moving costs associated with the sale. The guarantors also challenge the bank’s appraisal of the equipment, and state that the bank refused to permit two of the guarantors to assemble the equipment prior to the sale, and refused to permit prospective buyers to examine the equipment prior to the sale, which refusal allegedly had a chilling effect on the sale. Additionally, the guarantors state that the bank unreasonably refused to offer a valuable patent for sale. Further, the guarantors attest that the collateral was sold for an insufficient price and that the bank did not bid at the sale as it had originally indicated it would.
1. Guarantors’ Right to Challenge the Commercial Reasonableness of the Disposition of the Collateral by the Secured Party.
Pursuant to G. L. c. 106, § 9-504 (1), “[a] secured party after default may sell . . . any or all of the collateral in its then condition or following any commercially reasonable preparation or processing.” Also, pursuant to G. L. c. 106, § 9-504 (3) (1984 ed.), “[ejvery aspect of the disposition including the method, manner, time, place and terms must be commercially reasonable.” As provided in G. L. c. 106, § 9-501 (3) (b), the above cited provisions of § 9-504 (1) and (3) may not be waived or varied, “[t]o the extent that they give rights to the debtor and impose duties on the secured party.” There appears to be no dispute that the defendants entered into agreements with the bank absolutely and unconditionally guaranteeing payments of certain obligations of Rim, including the promissory notes that form the basis of this appeal. Further, the defendants *277 do not dispute that, through the language of the guaranties, they have agreed to waive defenses to any deficiency action, if the waiver is held to be valid. 4 Rather, the defendants contend that, pursuant to the provisions of G. L. c. 106, § 9-504 (1) and (3) (1984 ed.), they have the right to challenge the commercial reasonableness of the bank’s disposition of the collateral and, further, that G. L. c. 106, § 9-501 (3) (b) (1984 ed.), renders ineffective any waiver of their privilege to raise this defense.
The bank claims that, as guarantors, the defendants are not debtors within the meaning of these statutory provisions, that the defendants may not assert the defenses available to debtors under § 9-504 (1) and (3), and that, even if the defendants are able to assert these defenses, guarantors, unlike debtors, may waive the defenses prior to the default.
Whether a guarantor may assert the rights to a fair and commercially reasonable disposition of the collateral depends on whether a guarantor falls within the definition of “debtor” in § 9-105 (d). Section 9-105 (d) defines “debtor” as follows: “the person who owes payment or other performance of the obligation secured, whether or not he owns or has rights in the collateral, and includes the seller of accounts or chattel paper. Where the debtor and the owner of the collateral are *278 not the same person, the term ‘debtor’ means the owner of the collateral in any provision of the Article dealing with the collateral, the obligor in any provision dealing with the obligation, and may include both where the context so requires.” A guarantor is certainly a “debtor” within the statutory definition because the guarantor, after default by the principal obligor, “owes payment.” See Black’s Law Dictionary 634 (rev. 5th ed. 1979) (a guaranty is a promise to answer for the payment of a debt or the performance of an obligation if the person primarily liable in the first instance fails to make payment or perform the obligation). Because § 9-504 establishes the rights and duties of a secured party and the corresponding rights and remedies of a debtor in a default situation, the section deals with the collateral, which in this case the primary debtor owns, and the obligation, which forms the basis for the bank’s action for the deficiency judgment. In the default situation, the guarantor becomes liable on the obligation, the amount of which ultimately depends on the price realized from the secured party’s disposition of the collateral. The collateral and the obligation are thus so inextricably intertwined that we infer that it was the legislative intent to treat primary debtor and guarantor alike in the context of § 9-504 (1) and (3). Thus we conclude that in this context a guarantor falls within the definition of “debtor.”
The majority of jurisdictions construing the language of § 9-105 (d), which defines “debtor,” have found that guarantors , accommodation makers, and other obligors who owe a collat *279 eral duty to pay deficiencies are debtors within the meaning of Article 9. 5 Commentators also have advocated this position. 6
2. Waiver of the Commercial Reasonableness Defense.
From our conclusion that a guarantor is a debtor for purposes of § 9-504 (1) and (3), it follows that the provisions of § 9-501 (3) (b), which render the rights of a debtor and the duties of a secured party prescribed by § 9-504 (1) and (3) nonwaivable, apply to guarantors as well. As we have noted, the guarantor
*280
is the real debtor for all practical purposes after default, and we have inferred that the Legislature intended to treat both debtor and guarantor alike as to the defenses here in issue. Ample authority in other jurisdictions supports this result.
7
While there are cases reaching the opposite conclusion,
8
the better course is to apply the provisions of § 9-504 (1) and (3) aimed at protecting the rights of debtors to all guarantors who have the obligations of debtors in the default situation. The two Massachusetts cases where guarantors were held to be bound to their waiver of rights after default are inapposite as they did not occur in contexts, like the situation here, where there is an express legislative provision to preclude waiver of the rights at issue. See
Provident Co-op. Bank v. James Talcott, Inc.,
*281 3. Application of the Waiver Rule to this Case.
Our resolution of the first two issues in this case necessitates consideration of the bank’s contention at oral argument that any rule precluding guarantors from waiving certain article 9 defenses to the disposition of collateral should be applied prospectively to avoid disruptions in established commercial practice. We disagree. There is nothing in the record to show any such established commercial practice. More importantly, although this court has not previously dealt with the issues raised here, we are not announcing common law rules but rather are construing certain statutory provisions. Those provisions have had the same meaning since the effective date of the statutes. See
Commonwealth
v.
Cass,
4. Summary Judgment.
Our conclusions concerning the first three issues in this case require that we determine whether, on the basis of the affidavits submitted by the parties, summary judgment was properly granted. “Pursuant to Mass. R. Civ. P. 56 (c),
“In considering a motion for summary judgment, the court does not ‘pass upon the credibility of witnesses or the weight of the evidence [or] make [its] own decision of facts. ’”
Attorney Gen.
v.
Bailey, supra
at 370, quoting
Hub Assocs.
v.
Goode,
*282
The issue of the reasonableness of a secured party’s custody and disposition of collateral is a matter which may properly be decided on a motion for summary judgment. See
Federal Deposit Ins. Corp.
v.
Air Atl., Inc.,
5. Conclusion.
The bank may obtain a deficiency judgment on remand by demonstrating that its disposition of the collateral was commercially reasonable and that the amount realized from the sale failed to satisfy the remaining indebtedness. If the bank is not successful in demonstrating that the disposition of the collateral
*283
was commercially reasonable, the bank may still obtain a deficiency judgment in the amount of the debt owing, reduced by any loss resulting from the bank’s failure to adhere to the provisions of § 9-504 (1) and (3). See
Poti Holding Co.
v.
Piggott,
The judgment of the Superior Court is reversed and the case is remanded for further proceedings consistent with this opinion.
So ordered.
Notes
The judge granted the bank’s motion for summary judgment without opinion, but cited as authority for his decision
Federal Deposit Ins. Corp.
v.
Hill,
David Miller was treasurer, and Edwin B. Carton was president of Rim. Judah Graulich was a principal stockholder.
At oral argument and in their brief the defendants have not disputed these points.
The guaranties provided in relevant part: “The Guarantor waives: notice of appearance hereof, notice of any action taken or omitted by the Bank in reliance hereon, and any requirement that the Bank be diligent or prompt in making demands hereunder, giving notice of any default by the Borrower (except where notice is required by the terms of the Obligation) or asserting any other right of the Bank hereunder. The Guarantor also irrevocably waives, to the fullest extent permitted by law, all defenses which at any time may be available in respect of the Guarantor’s obligations hereunder by virtue of any homestead exemption, statute of limitations, valuation, stay, moratorium law or other similar law now or hereafter in effect.” In addition, the guaranties provided: “The Bank shall be at liberty, without giving notice to or obtaining the assent of the Guarantor and without relieving the Guarantor of any liability hereunder, to deal with the Borrower and *278 with each other party who now is or after the date hereof become liable in any manner for any of the Obligations, in such manner as the Bank in its sole discretion deems fit.”
See
Ford Motor Credit Co.
v.
Lototsky,
A few courts have taken a contrary position. See
A.J. Armstrong Co.
v.
Janburt Embroidery Corp.,
See Sachs & Belgrad, Liability of the Guarantor of Secured Indebtedness After Default and Repossession Under the Uniform Commercial Code: A Walk on the Wild Side by the Secured Party, 5 U. Balt. L. Rev. 153, 161 (1976); Clark, Suretyship in the Uniform Commercial Code, 46 Tex. L. Rev. 453, 477-478 (1968).
See
United States
v.
Lang,
See
First Nat’l Park Bank
v.
Johnson,
