Micromuse Settles Class Action

SAN FRANCISCO -- Micromuse Inc. (Nasdaq: MUSE - News), the leading provider of ultra-scalable, realtime business and service assurance software, announced today that it has reached an agreement to settle the consolidated securities class action entitled In Re: Micromuse Inc. Securities Litigation, Case No. C-04-0136 SBA, pending in the U.S. District Court for the Northern District of California against the Company and a number of the Company's current and former officers and related to the Company's restated financial statements filed May 17, 2004. In addition, the Company settled a related shareholder derivative suit, Sutterfield v. Carney et al., Case No. C-04-0893 SBA, pending in the same court.

Under the proposed settlement, the lawsuits will be terminated in exchange for a payment that will have no material adverse financial impact on the Company, as it will be covered largely by the Company's insurance policies. This settlement has been reached with no admission of liability by any party and has been entered into to avoid costly and time consuming litigation by all parties. All parties have agreed to expeditiously seek the required court approvals of the settlement. As part of the settlement, the Company made no admission of wrongdoing.

Micromuse Inc.