
371 Mass. 404 (1976)
357 N.E.2d 762
DONALD P. BABSON & others[1]
vs.
BOSTON RENT CONTROL ADMINISTRATOR.
Supreme Judicial Court of Massachusetts, Suffolk.
November 3, 1976.
December 1, 1976.
Present: HENNESSEY, C.J., QUIRICO, BRAUCHER, WILKINS, & LIACOS, JJ.
Mark Snyder for the defendant.
Alix Smullin (Joseph L. Cotter with her) for the plaintiffs.
WILKINS, J.
We agree with a judge of the Housing Court of the City of Boston who ruled, under St. 1970, c. 842, § 6 (a), that the base maximum rent of a controlled rental unit ("the rent charged the occupant for the month six months prior to the acceptance of this act by a municipality") includes amounts payable by tenants under the terms of tax escalation clauses in their leases.
The defendant rent control administrator issued rent Regulation 1, § 5 of which purported to exclude from the *405 maximum rent any tax increment on account of tax increases announced by the city of Boston after the base month. Here, the units became subject to rent control on January 1, 1973, and the maximum permissible rents were those in effect for July, 1972. In the fall of 1973, the local real estate tax bill for the premises was issued and additional rent was due from tenants under the tax escalation clauses in their leases. Because the local tax rate remained stable from 1972 to 1973 the additional rent due in 1973 was substantially equivalent to the additional rent payable in 1972 under the tax escalation clauses.
This bill for review and for declaratory relief challenges the administrator's determination, pursuant to his regulation, that the landlord was not entitled to charge, collect, or retain the additional rent payable under the tax escalation clauses of the various leases. The judge ruled in favor of the landlord, and the defendant appealed. We transferred the appeal here for disposition. There was no error.
We have no difficulty in concluding that "the rent charged ... for" July, 1972, included amounts later determined to be payable with respect to that month. It is plain that the additional obligation was "rent,"[2] and equally plain that under the tax escalation clauses that rent was "charged" in proportionate part for July, 1972. The conclusion we reach is the same as that reached in substantially similar circumstances in Woods v. Callahan, 172 F.2d 179 (1st Cir.1948).
Because the statute is unambiguous in this respect, the defendant's regulation to the contrary exceeds his authority and is invalid, and we need not consider whether, in resolving an ambiguity in a statute applicable to more than one municipality, we should look for guidance in its interpretation to a regulation issued in a single municipality.
Judgment affirmed.
NOTES
[1]  For the disposition of this case it is unnecessary to set forth or to consider the status of the various plaintiffs. It is sufficient to treat them collectively as the landlord.
[2]  Statute 1970, c. 842, § 3 (c), defines "rent" as "the consideration ... for or in connection with the use or occupancy of rental units...."
