Any taxpayers considering taking an alternative apportionment position on its corporate excise tax returns this fall should remember that the Department adopted a revised alternative apportionment regulation, 830 CMR 63.42.1, which is applicable to the 2016 tax year. Under the regulation, a taxpayer must file a request for alternative apportionment when it files its tax return. However, even if a timely request for alternative apportionment is submitted, the taxpayer must still pay tax computed based on the statutory apportionment rules. If the Department grants the taxpayer’s request for alternative apportionment, then the taxpayer must file a refund claim using the approved alternative apportionment method. The alternative apportionment regulation sets a higher bar for a taxpayer than for the Commissioner in asserting the need for alternative apportionment. A taxpayer seeking to use an alternative apportionment method must show by “clear and cogent evidence that the income attributed to Massachusetts using statutory apportionment does not fairly represent the extent of the [taxpayer’s Massachusetts business activity].” On the other hand, the regulation provides the Department may assert the need to use an alternative apportionment method based on the “Commissioner’s judgment.” There may be an opportunity to challenge the validity of these standards. The alternative apportionment statute, G.L. c. 63, § 42, does not contemplate different standards for the taxpayer and Commissioner. As such, the regulation may be invalid as contrary to Massachusetts statute.