Thе issue we address in this case is whether a 2008 amendment to the enforcement section of the Massachusetts Wage Act, G. L. c. 149, § 150 (§ 150), providing for a mandatory award of treble damages to a prevailing employee, should be *475 applied in an action brought by an employee against her employer for violation of the Wage Act before the amendment’s effective date. We conclude that the amendment should be read to apply only prospectively, to claims arising on or after the amendment’s effective date of July 12, 2008. Because the Superior Court judge applied the amendment retrospectively to this case, we remand to the Superior Court for further proceedings consistent with this opinion. 1
1. Background'. 2 The plaintiff, Elena Rosnov, worked as an attorney in the law office of the defendant, John H. Molloy, from early February, 2006, until her resignation on June 26, 2006. As a term of her employment, Rosnov was to be provided a referral fee of forty per cent of any contingency fee that Mol-loy or his office received in connection with the settlement or damage award in any case that Rosnov referred to Molloy. In March of 2007, a case that Rosnov had referred to Molloy the preceding year reached a partial settlement of $2.5 million. Ultimately, Molloy received attorney’s fees in connection with the partial settlement in the amount of $432,500.
On April 17, 2007, Rosnov filed a complaint in the Superior Court against Molloy, claiming his failure to pay her a referral fee connected to the case was a breaсh of contract and violated the Wage Act, G. L. c. 149, §§ 148, 150 (Wage Act). 3 She sought to recover a portion of the attorney’s fees Molloy had received. By agreement of the parties, the trial was bifurcated, and the liability portion of Rosnov’s contract claim was tried to a jury without reference to damages; the parties agreed that if there was liability on the contract claim, the amount of contract damages was $173,000, or forty per cent of $432,500. In March, 2009, a jury found that an oral contract for the division of fees *476 existed between Rosnov and Molloy, and that Molloy had breached the contract by not providing Rosnov a referral fee. Thereafter, the trial judge considered, without a jury, whether Rosnov’s referral fee constituted a “commission” under the Wage Aсt, and if so, whether Rosnov was entitled to treble damages under § 150.
The judge found that Rosnov was an employee under the Wage Act and that the fee qualified as a commission. The judge further concluded the version of § 150 amended after this case was filed applied, “because violators of the Wage Act have always been subject to treble damages. . . . This is not a case where the аmendment to the statute substantially changes parties’ rights and expectations.” 4 The judge thus concluded that Rosnov was entitled to a mandatory award of treble damages, or $519,000, plus interest. Molloy appealed, and we granted his application for direct appellate review. 5
2.
Discussion.
As earlier indicated, the only question we address is which version of § 150 should be applied in this case: § 150, as amended through St. 2008, c. 80, § 5 (chapter 80), effective July 12, 2008; or § 150, as amended through St. 2005, c. 99, § 2, the version of the statute in effect in 2007 when Rosnov filed her complaint. This is a question of statutory interpretation, and therefore one that we review de novo. See, e.g.,
Commerce Ins. Co.
v.
Commissioner of Ins.,
a.
Statutory retroactivity.
The presumption that statutes operate prospectively is well established.
Fleet Nat’l Bank
v.
Commissioner of Revenue,
“In the absence of an express legislative directive, this court has usually applied ‘[t]he general rule of interpretation . . . that all statutes are prospective in their operation, unless an intention that thеy shall be retrospective appears by necessary implication from their words, context or objects when considered in the light of the subject matter, the pre-existing state of the law and the effect upon existent rights, remedies and obligations. Doubtless all legislation commonly looks to the future, not to the past, and has no retroactive effect unless such effect manifestly is rеquired by unequivocal terms. It is only statutes regulating practice, procedure and evidence, in short, those relating to remedies and not affecting substantive rights, that commonly are treated as operating retroactively, and as applying to pending actions or causes of action.’ ”
Fontaine
v.
Ebtec Corp.,
Rosnov argues that the presumption of prospective application does not apply to chapter 80 for two reasons: because the statute relates only to remedies and not to substantive rights; and because the legislative history of this amendment evinces an intent on the part of the Legislature that the amendment be applied retroactively. Conversely, Molloy contends that chapter 80 pertains to substantive rights because it alters the extent of a party’s liability; and that in any event there is insufficient evidence of a clear legislative intent that chapter 80 be retroactively applied. For the reasons that follow, we agree with Molloy. 6
b. Substantive right. Before chapter 80 was passed, the relevant *478 portion of § 150, as amended through St. 2005, c. 99, § 2, read as follows:
“Any employee claiming to be aggrieved by a violation of [the Wage Act or certain other statutes] may, at the expiration оf ninety days after the filing of a complaint with the attorney general . . . institute and prosecute in his own name and on his own behalf, or for himself and for others similarly situated, a civil action for injunctive relief and any damages incurred, including treble damages for any loss of wages and other benefits. An employee so aggrieved and who prevails in such an action shall be entitled to an award of the costs of the litigation and reasonable attorney fees” (emphasis supplied).
In
Wiedmann
v.
Bradford Group,
The Wiedmann case was decided on July 21, 2005. Effective *479 July 12, 2008, three years later, the provision of § 150 concerning treble damages was amended as follows:
“An employee so aggrieved who prevails in such an action shall be awarded treble damages, as liquidated damages, for any lost wages and other benefits and shall also be awarded the costs of the litigation and reasonable attorneys’ fees” (emphasis supplied).
Chapter 80 effected a critical change in the language of the statute, removing the provision that treble damages “may” be awarded, and replacing it with the directive that treble damagеs “shall be awarded.” See Wiedmann, supra at 710, and cases cited (“may” is permissive; “shall” imposes mandatory obligation).
We recognize that “the distinction between legislation that concerns ‘substantive rights,’ and legislation that concerns ‘procedures’ and ‘remedies,’ has proved to be difficult to draw.”
Fontaine
v.
Ebtec Corp.,
*480
Similarly, in this case, where only a potential for treble damages existed before, certainty of their imposition is now the rule. The 2008 amendment to § 150 increases a defendant’s measure of liability because the discretion of a judge
not
to award treble damages — where, for example, the judge did not find the defendant’s conduct to have been outrageous or recklessly indifferent, see
Wiedmann,
c.
Legislative intent.
By its terms, chapter 80 gives no indication the Legislature intended that the amended version of § 150 be applied retroactively. See
Fleet Nat’l Bank
v.
Commissioner of Revenue,
The undertaking to amend the treble damage provision of *481 § 150 began before the Wiedmann case was decided in July of 2005. See 2005 House Doc. No. 3775; 2005 Senate Doc. No. 928. Subsequent to the decision in Wiedmann, a new draft of these bills was filed, first as 2005 House Doc. No. 4343, and then as 2006 House Doc. No. 4663. The preamble of 2006 House Doc. No. 4663 stated that “the purpose of this Act is to clarify the language of thе statute to reiterate the intent of the Legislature that such treble damages be mandatory.” The treble damages clause proposed in 2006 House Doc. No. 4663 read:
“Any employee so aggrieved and who prevails in such an action shall be awarded treble damages, as liquidated damages, for any loss of wages and other benefits; and such employee shall also be awardеd the costs of the litigation and reasonable attorneys’ fees.”
House Doc. No. 4663 passed both the House of Representatives and the Senate, but then was vetoed by the Governor and was never enacted. 2006 House J. 2203.
Rosnov nonetheless points to 2007 Senate Doc. No. 1059, which ultimately was enacted in 2008 as chapter 80. Senate Doc. No. 1059 was entitled “An Act to clarify the law prоtecting employee compensation,” and included a separate section (§ 8) that identified the purpose of the act as clarifying the existing law and “reiterat[ing] the original intention of the general court that triple damages are mandatory.” At some point — it may have been while the bill was in third reading 8 — the title changed to “An Act further regulating employee compensation,” and that § 8 was removed.
As a general rule, when language is removed from a bill before its final passage, we presume its deletion to have been intentional. See
Green
v.
Wyman-Gordon, Co.,
We are unconvinced that Rosnov’s assumption about the Legislature’s thought process is correct; the best that can be said is that the Legislature’s intent on the retroactivity issue is murky. Certainly, chapter 80 does not reflect the “unequivocally clear” legislative intent required for this court to decide in favor of retrospective aрplication.
9
See, e.g.,
Sentry Fed. Sav. Bank
v.
Co-operative Cent. Bank,
Rosnov also focuses on the fact that chapter 80 originated in the Senate two years after this court’s decision in Wiedmann; she finds in this timing further support for her position that in enacting chapter 80, the Legislature was only clarifying and restаting its original position in relation to mandatory treble damage awards, not changing it. We disagree.
It is true that this court has interpreted “swift legislative action in the wake” of a contrary judicial ruling to evince legislative intent to clarify its position on the issue.
Swift
v.
AutoZone, Inc.,
3. Conclusion. Because we conclude the 2008 amendment to G. L. c. 149, § 150, does not apply retroactively to the present case, we vacate the judgment as to damages against Molloy and remand the case to the Superior Court for consideration whether treble damages are appropriate under the standard set out in Wiedmann v. Bradford Group, 444 Mass, at 709-710. 10
So ordered.
Notes
We acknowledge the amicus briefs of the New England Legal Foundation and Associated Industries of Massachusetts; Massachusetts Employment Lawyers Association, Greater Boston Legal Services and affiliated organizations; and William J. Okerman.
The facts recited here are taken primarily from the Superior Court judge’s memorandum of decision on the plaintiff’s motion for posttrial treble damages; the remaining facts recited appeаr to be undisputed.
With respect to the Wage Act claim, Elena Rosnov first obtained a right to sue letter from the Attorney General, as required by G. L. c. 149, § 150 (§ 150).
As we discuss in the text infra, effective July 12, 2008, the Legislature amended § 150 to include the mandatory imposition of treble damages for violations of § 150. G. L. c. 149, § 150, as amended through St. 2008, c. 80, § 5 (chapter 80). Beginning in 1993, § 150 had provided for treble damages, see St. 1993, c. 110, § 182, but the pertinent language of the statute was different.
On appeal, Molloy does not contest the Superior Court judge’s conclusions either that Rosnov was an “employee” or that she was paid a “commission” within the meaning of the Wage Act.
Molloy argues briefly that, by mandating treble damages, this statute is “constitutionally suspect,” and that retroactive application of chapter 80
*478
would violate Ms due process rights under the United States Constitution and the Massachusetts Declaration of Rights. Because we conclude chapter 80 does not apply retroactively to the conduct at issue in this case, we need not consider these constitutional arguments. See
Landgraf
v.
USI Film Prods.,
In
Wiedmann
v.
Bradford Group,
In their briefs, the parties appear to agreе that these changes occurred during third reading, but at oral argument, counsel for Molloy expressed some uncertainty about the timing of the changes.
After the Legislature passed chapter 80, the Governor sought amendments that would have allowed for an exception to mandatory treble damages for employers who act in good faith. When the Legislature declined to acсept the proposed amendments, chapter 80 became law without the Governor’s signature. Rosnov cites the Senate’s rejection of the Governor’s proposed amendments as demonstrating that the Legislature intended chapter 80 as a response to Wiedmann and that chapter 80 should therefore be retroactively applied. The argument fails. The Legislature’s rejection of the Governor’s amendments tells us nothing about whether the Legislature intended its continued adherence to chapter 80 as passed to operate retroactively. Instead, this rejection demonstrates only that the Legislature wanted the law, at least going forward, to provide mandatory treble damages for any violation of the Wage Act.
Rosnov filed in this court a motion for “partial summary disposition” relative to her award of single damages. The Superior Court may consider this motion on remand.
