Mass. Gen. Laws ch. 55 § 26
The city or town clerk shall retain all statements and reports required to be filed with such clerk until December 31st of the sixth year following the relevant election. In the case of committees other than those authorized by a candidate, the city or town clerk shall retain all required statements and reports filed with such clerk until December 31st of the sixth year following the date that the statement or report was filed. Such statements and reports shall be available for convenient public inspection and copying at the office of the city or town clerk during normal business hours as soon as such statements and reports are filed with him. Within 30 days after the filing deadline, all campaign finance reports required to be filed with the city or town clerk under section 18 shall be made available for viewing on the internet website of the municipality if such municipality has such a website, if the report discloses that a candidate or committee filing a report has received contributions or made expenditures in excess of $1,000 during a reporting period or incurred liabilities or acquired or disposed of assets in excess of $1,000 during a reporting period.
Mass. Gen. Laws ch. 55, § 26