SUPREME COURT OF CALIFORNIA MONTROSE CHEMICAL CORPORATION OF CALIFORNIA, Petitioner, v. THE SUPERIOR COURT OF LOS ANGELES COUNTY, Respondent; CANADIAN UNIVERSAL INSURANCE COMPANY, INC., et al., Real Parties in Interest. April 6, 2020 EXCERPTS/SUMMARY BY JUNFOLA 4 7 20

Reading the policy in light of principles of insurance law and the reasonable expectations of the parties, Montrose is entitled to access available coverage under any excess policy once it has exhausted directly underlying excess policies for the same policy period.  A rule of vertical exhaustion is appropriate.  The insured has access to any excess policy once it has exhausted other directly underlying excess policies with lower attachment points, but an insurer called upon to indemnify the insured’s loss may seek reimbursement from other insurers that issued policies covering relevant policy periods.