We issued a writ of certiorari to review the court of appeals' judgment in Nationwide Mutual Fire Ins. Co. v. Clementi,
We granted certiorari to determine whether the Clementis' notice was untimely and whether Nationwide was required to demonstrate prejudice before forfeiting benefits under the UIM policy in question. We now reverse the court of appeals and expressly adopt the notice-prejudice rule in UIM cases. We decline to overrule Mares at this time becаuse we find that its holding applies only to liability cases and is thus inapplicable to this case. However, to the extent that Ma-rez has been applied by the court of appeals to UIM cases, we disapprove.
I. FACTS AND PROCEDURAL HISTORY
On March 11, 1994, James Clementi, a Colorado state trooper, was injured in an automobile accident while acting within the course and scope of his employment. In August 1994, Clementi was notified by State Farm that the other driver's policy was limited to $50,000. The following spring, Clemen-tis physician determined that he had reached maximum medical improvement and had sustained a seventeen percent impairment rating. In March 1995, Clementi was awarded workers' compensation benefits of approximately $43,000. Clementi gave notice to Nationwide of his UIM claim for damages exceeding the State Farm and workers' compensation benefits in August 1995, seventeen months after the accident. In April 1996, Clementi received $50,000 from State Farm, pursuant to a settlement agreement.
Nationwide filed suit, seeking a declaratory judgment voiding the Clementis' UIM coverage because of their alleged failure to give timely notice of their claim as required by their policy. The trial court determined that the latest date upon which Clementi could have ascertained with reasonable diligence that the other driver was underinsured was March 1995, when Clementi learned that *225 he had a seventeen percent disability and knew that his actual damages were already approaching the other driver's policy limits. The court found that the Clementis' unexplained failure to notify Nationwide of their potential UIM claim until five months after this date was unreasonable. The court found that the language in the policy requiring that notice be provided "as soon as practicable" was not ambiguous within the context of Colorado case law. The court also recognized that the policy reason for enforcing notice requirements is to allow insurers to investigate and protect against false claims. Finally, the court rejected the Clementis argument that Nationwide should be required to show prejudice from their late notice in order to void their UIM benefits. Citing Mares, the court noted that Colorado law appeared to require no such showing. Thus, the trial court granted Nationwide's motion for summary judgment and declared the Clementis®' UIM coverage null and void.
On appeal, the court affirmed the trial court's ruling, holding that the policy's language requiring notice "as soon as practicable" was not ambiguous, and that it did not violate public policy. Clementi,
We granted certiorari to determine whether the trial court properly granted summary judgment in favor of Nationwide on the basis that the Clementis' notice was untimely as a matter of law and on the basis that Nationwide was not required to demonstrate prejudice before it could forfeit the Clementis' UIM benefits. 1
II. ANALYSIS
This case presents an opportunity for us to address the status of the so-called notice-prejudice rule
2
in Colorado. Nearly twenty years ago, this court refused to adopt the notice-prejudice rule in a liability insurance case, holding that in denying benefits, an insurer is not required to demonstrate that it was prejudiced by an insured's failure to comply with a policy's notice requirements. See Mares,
A. Standard of Review
We are reviewing the trial court's grant of Nationwide's motion for summary judgment under C.R.C.P. 56. Under this rule, a motion for summary judgment should be granted only when there are no issues of material fact. C.R.C.P. 56; Bebo Constr. Co. v. Mattox & O'Brien, P.C.,
B. Timeliness of Notice
The Clementis' policy requires an insured to "submit written proof of the claim . as soon as praсticable." R. at 68. The Clementis did not notify Nationwide of their UIM claim until seventeen months after the accident. The trial court found that at the latest, the Clementis should have provided Nationwide notice of their UIM claim five months before notice was actually given. The court found that the Clementis' unexplained delay was unreasonable as a matter of law. The Clementis argue that the trial court erred in holding that their notice was untimely because it was given seven months before their settlement with State Farm, and thus was in substantial compliance with the terms of the policy. We disagree.
A policy's requirement of notice "as soon as practicable" means that notice must be given within а reasonable length of time under the cireumstances. Certified Indem. Co. v. Thun,
The court of appeals has held that a delay is justified when the purposes of the notice provision are met by actual notice to the insurer, whether or not made in strict compliance with the policy. Hansen v. Barmore,
In the present case, however, the Clementis did not provide notiсe to Nationwide until five months after they reasonably could have known about their claim. The duty to give notice under a UIM policy arises when an insured, with reasonable diligence, can ascertain that the alleged tortfeasor is underinsured. Prudential Prop. & Cas. Ins. Co. v. LaRose,
Having thus determined that the Clemen-tis notice was untimely, we now address whether Nationwide should have been required to show that it had been prejudiced by the Clementis' untimely notice before denying them of their benefits.
C. Notice-Prejudice Rule
Traditional Approach
Traditionally, courts did not consider prejudice in late-notice cases. Charles C. Marvel, Annotation, Modern Status of Rules Requiring Liability Insurer to Show Prejudice to Escape Liability Because of Insured's Failure or Delay in Giving Notice of Accident or Claim, or in Forwarding Suit Papers, 82 A.L.RAth 141 (1984); John A. Ap-pleman & Jean Appleman, Insurance Law & Practice § 5088.35, at 292 (1981). The traditional approach is grounded upon a strict contractual interpretation of insurance policies under which delayed notice was viewed as constituting a breach of contract, making the issue of insurer prejudice immaterial. See Aetina Cas. & Sur. Co. v. Murphy,
For twenty-five years, Colorado has adhered to the traditional approach that an unexcused delay in giving notice relieves the insurer of its obligations under an insurance policy, regardless of whether the insurer was prejudiced by the delay. See Mares,
In Mares this court refused to deрart from the traditional approach and require an insurer to demonstrate that it was prejudiced by an insured's failure to comply with the notice requirements of a liability policy in order to deny benefits
We declined to join those jurisdictions that had adopted the modern approach and allow the petitioners to show that the insurer had not been prejudiced by their failure to comply with the policy's notice requirements. Id. at 290. We noted that Colorado had consistently followed the traditional approach, which was the majority rule at the time. Id. We reasoned that adopting the notice-prejfudice rule would negate the purpose of the notice requirements, and сoncluded that the salutary purposes of the notice provisions should not be set aside without substantial justification. Id. at 291. We held that the case did not provide a factual context compelling a departure from the traditional approach, noting that "it is jurisprudentially sound to leave the matter to another day, or to the wisdom of the general assembly." Id. 3 , 4
The court of appeals has applied Mares in various contexts involving both liability insur
*228
ance and UIM policies. Estate of Rick Harry By & Through Harry v. Hawkeye-Security Ins. Co.,
However, because Mares involved a no-notice liability case, we find that Maree is inapplicable in determining whether insurer prejudice should be considered in the UIM late-notice case at bar. 5 Accordingly, we now address whether the notice-prejudice rule should apply to UIM cases in Colorado. In doing so, we review the case law in other jurisdictions on this issue in light of Colorado's treatment of UIM policies.
Few courts today strictly adhere to the traditional approach which allowed for no consideration of insurer prejudice in determining whether benefits should be denied due to noncompliance with an insurance policy's notice requirements. Alcazar,
*229 Modern Trend
Courts that have joined the modern trend by adopting the notice-prejudice rule consider insurer prejudice in determining whether the insurer may deny benefits in late-notice cases. Alcazar,
Courts have articulated three policy justifications for departing from the traditional approach. These justifications can be generally described as follows: (1) the аdhesive nature of insurance contracts, (2) the public policy objective of compensating tort victims, and (8) the inequity of the insurer receiving a windfall due to a technicality. Alcazar,
In Brakeman, the Pennsylvania Supreme Court rationalized its departure from the traditional approach in part by noting that such an approach fails to recognize the true nature of the relationship between insurance companies and their insureds.
Indeed, this court has recognized the unequal bargaining power of the parties to an insurance policy. "Because of both the disparity of bargaining power between insurer and insured and the fact that materially different coverage cannot be readily obtained elsewhere, automobile insurance policies are generally not the result of bargaining." Huizar v. Allstate Ins. Co.,
Courts that have adopted the notice-prejudice rule have also recognized the public interest in enforcing automobile insurance contracts to further the goal of compensating tort victims, including innocent third parties. Brakeman, 371 A.2R
The Colorado legislature has recognized the public interest in compensating accident victims by enacting the Motor Vehicle Financial Responsibility Act at sections 42-7-101 to -609, 11 C.R.S. (2000), and the Colorado Auto Accident Reparations Act at sections 10-4-701 to -726, 8 C.R.S. (2000). In enacting thе Motor Vehicle Financial Responsibility Act, the general assembly stated that it was "very much concerned with the financial loss visited upon innocent traffic accident victims by negligent motorists who are financially irresponsible." § 42-7-102, 11 C.R.S. (2000). The general assembly further noted that "it is the policy of this state to induce and encourage all motorists to provide for their financial responsibility for the protection of others, and to assure the widespread availability to the insuring public of insurance protection against financial loss caused by negligent financially irresponsible motorists." Id.
Also, by enacting the Colorado Auto Accident Reparations Act, the legislature specifically sought to "avoid inadequate compensation to victims of automobile accidents." § 10-4-702. Indeed, in Marez, we deferred to the wisdom of the legislature in light of the significance of its "sweeping revisions of
*230
the Colorado insurance law [reflected in] the adoption of the 'Colorado Automobile Aceci-dent Reparations Act'"
Courts that have adopted the notice-prejudice rule have also expressed concern for the severity of forfeiting one's insurance benefits based on the technical violation of a notice provision. See, eg., Brakeman, 871 AZ2d at 198 (reasoning that "[alllowing an insurance company, which has collected full premiums for coverage, to refuse compensation to an accident victim or insured on the ground of late notice, where it is not shown timely notice would have put the company in a more favorable position, is unduly severe and inequitable").
9
Some courts that have taken this position have pointed to the Restatement (Second) of Contracts, which states that: "To the extent that the non-occurrence of a condition would cause disproportionate forfeiture, a court may exeuse the non-occurrence of that condition unless its occurrence was a material part of the agreed exchange." Restatement (Second) of Contracts § 229 (1981). These courts hold that when an insurer is not prejudiced, an insured's failure to comply with a notice requirement is excused, since a "disproportionate forfeiture" ensues from enforcing such a requirement. Alcazar,
Indeed, in Colorado, an analogous line of reasoning has been employed to invalidate insurance provisions that are void as against public policy. As relevant here, Colorado courts have refused to enforce certain provisions in UIM policies whose enforcement would result in some forfeiture of coverage. Peterman v. State Farm Mut. Auto. Ins. Co.,
Thus, in light of Colorаdo's recognition of the policy reasons underlying the notice-prejudice rule, we are persuaded by the reasoning of courts that have joined the modern trend and conclude that insurer prejudice should now be considered when determining whether noncompliance with a UIM policy's notice requirements vitiates coverage. Having adopted the notice-prejudice rule in Colorado UIM cases, we now address the appropriate treatment of insurer prejudice in an evaluation of such cases.
Burden of Proof
Courts that have adopted the notice-prejudice rule by considering insurer prejudice in determining whether a denial of benefits is justified by noncompliance with a policy's notice requirements have done so in various ways. A plurality of courts have held that once it is evident that the insured breached the notice provision, the burden of proof should fall upon the insurer to prove that it has been prejudiced by the breach. Ouellette, 495 AZ2d at 1234; Alcazar,
In Brakeman, the court reasoned that "although it may be difficult for the insurance company to prove it suffered prejudice as a consequence of an untimely notice, it appears to us that it would be at least as difficult for the claimant to prove a lack of prejudice."
Some courts have held that when the insured fails to comply with a policy's notice requirements, a presumption that the insurer was prejudiced by the breach arises. Seq, е.g., Gray v. State Farm Mut. Auto. Ins. Co.,
These courts reason that the insured is the party seeking to be excused from the consequences of violating a contract provision. Al-cazar,
A few courts have held that prejudice is a factor to be considered along with the insured's exeuse for the delay, the length of delay, and the sophistication of the insured, in determining the reasonableness of a delay in notice. Alcazar,
We find this approach problematic because we believe that insurer prejudice is not relevant to the reasonableness of the insured's delayed notice, and thus should not be considered as a factor. See Alcasar,
Having rejected the prejudice-as-a-factor approach, we now determine whether the burden of proving prejudice should be placed on the insurer or on the insured. We agree with the courts that have concluded that it is more difficult for an insured to prove a nega
*232
tive, that is, that the insurer was not prejfu-diced, than it would be for the insurer to demonstrate that it was hampered in its ability to investigate or defend a claim because of the insured's failure to provide timely notice. See, eg., Alcazar,
Application of Notice-Prejudicé Rule
Having thus adopted the notice-prejudice rule in Colorado UIM cases by assigning the burden of proving рrejudice to the insurer, we now apply this rule to the case at bar. As discussed above, we find that the trial court properly found that the Clementis' notice, which was given five months after the latest date on which they should have reasonably done so, was untimely as a matter of law, and that the Clementis' delay was unreasonable. See supra p. 226. Therefore, our final determination concerns whether Nationwide was prejudiced by the Clementis' delay.
As discussed above, an insurer is prejudiced by a delayed notice only when its ability to investigate or defend the insured's claim is compromised by the insured's failure to provide timely notice. See supra p. 229. Nationwide contends that Clemеnti's delay deprived it of its ability to pursue and protect its rights under the insurance policy.
The parties do not dispute that the accident in this case was investigated by the police, the workers' compensation carrier, and State Farm. The record also indicates that Nationwide had the opportunity to investigate the accident several months prior to the Clementis' settlement with State Farm. However, the record reveals no detailed evidence concerning the other investigations that would indicate whether they are adequate to protect Nationwide's rights under the policy.
Therefore, we reverse the court of appeals' judgment affirming the triаl court's grant of summary judgment in favor of Nationwide, and remand this case for a determination of whether Nationwide was prejudiced by the Clementis' delay.
CONCLUSION
Today, we expressly adopt the notice-prejudice rule in Colorado, as it applies to UIM cases. We hold that once it has been established that an insured has unreasonably provided delayed notice to an insurer, an insurer may only deny benefits if it can prove by a preponderance of the evidence that it was prejudiced by the delay. In the present case, the trial court properly found that the Clementis' notice was untimely as a matter of law. We conclude that because the record is insuffiсient to determine whether Nationwide was prejudiced by the Clementis' delay, the court of appeals erred in affirming the trial court's grant of summary judgment. Therefore, we reverse the court of appeals' decision and remand for further proceedings consistent with this opinion.
Notes
. We granted certiorari on the following issue: Whether the court of appeals erred in affirming the trial court, which held, as a matter of law, that the notice given by the Clementis to Nationwide, seven months before settlement with the tortfeasor, was not timely and that Nationwide was not required to demonstrate prejudice before it could forfeit underinsured motorist benefits.
. -See Burns v. Int'l Ins. Co.,
. Our research reveals only three jurisdictions in which a consideration of prejudice in late-notice cases has been mandated by the legislature: Georgia, Ga.Code Ann. § 33-7-15 (2000); Champion v. S. Gen. Ins. Co.,
. Three members of the court dissented in Marez.
. We need not consider today whether our ruling in Marez continues to apply to liability insurance cases because this issue is not presented by the case at bar. Cf. Alcazar,
. But cf. Fairmont Funding v. Utica Mut. Ins. Co.,
. See Washington Sports & Entm't v. United Coastal Ins.,
. But see Am. Justice v. Hutchison,
. Some courts have articulated this principle from an opposite view, that is, from the standpoint of the insurer. "If insurers were allowed to avoid payment based on the insured's conduct even in the absence of prejudice, the public policy of risk spreading would be compromised and, in a sense, the insurer would receive a windfall ." Kaplan v. Northwestern Mut. Life Ins. Co.,
. We decline to require that the insurer demonstrate substantial prejudice, as some courts have done. See, eg., White Caps,
