Section 10. For a period of fifteen years after the organization of any such corporation, such corporation and all its real and personal property, including all real and personal property leased by it from a housing authority or from a redevelopment authority or from a city or town or a corporation wholly owned or controlled by a city or town, shall be exempt from taxation and from betterments and special assessments; and for such period any such corporation shall not be required to pay any tax, excise, or assessment to or for the commonwealth or any of its political subdivisions; provided, however, that notwithstanding the foregoing provisions of this section, any such corporation shall be required to pay (1) the excises and sums respectively prescribed by this section and section fifteen; (2) excises assessed under chapter sixty A and acts in amendment thereof or addition thereto; and (3) excises imposed by chapter sixty-four A and acts in amendment thereof or addition thereto; and provided, further, that nothing in this section shall be construed to prevent any such corporation which enters into a contract under section fourteen from agreeing therein to make, or from making pursuant thereto, payments in lieu of betterments or special assessments.

Notwithstanding the foregoing provisions of this section, the assessors of every city or town in which real or tangible personal property exempted by this section from taxation under chapter fifty-nine is situated on January first of any year shall, on or before March first in such year, determine and certify to the commissioner of revenue and to the corporation organized under this chapter which owns or leases such property the fair cash value of such property as of January first in such year. On or before the first day of April then next ensuing, or within thirty days after the receipt of the certification of valuation from the assessors, whichever is later, such corporation, if aggrieved by such valuation, may appeal therefrom to the appellate tax board. Said board shall hear and decide the subject matter of such appeal and give notice of its decision to the commissioner of revenue, the assessors and the corporation; and, except as provided in section thirteen of chapter fifty-eight A, such decision shall be final and conclusive.

During the period of fifteen years after the organization of a corporation under this chapter, such corporation shall pay in each calendar year to the commonwealth with respect to its corporate existence at any time within the preceding calendar year an excise equal to the sum of the following: namely, an amount equal to five per cent of its gross income in such preceding calendar year, from all sources, and an amount equal to ten dollars per thousand upon the valuation determined as hereinbefore provided to be the fair cash value as of January first in the year in which the excise becomes payable of all real and tangible personal property of such corporation, including all real and tangible personal property leased by it which is exempted by this section from taxation under chapter fifty-nine; provided, that the excise payable in any year shall not be less than the amount which the city or town would receive for taxes, at the rate for such year, upon whichever of the following valuations is the lesser: (a) the valuation upon which the aforesaid amount equal to ten dollars per thousand is computed; or (b) the average of the assessed valuations of the land and all buildings and other things erected thereon or affixed thereto on the three assessment dates, in the case of land purchased, taken or leased by such corporation from a housing authority, redevelopment authority, city, town or corporation wholly owned or controlled by a city or town, next preceding the acquisition of the land by such housing authority, redevelopment authority, city, town or wholly owned or controlled corporation, and in the case of all other land purchased, taken or leased by a corporation organized under this chapter, next preceding the acquisition thereof by such corporation, the assessed valuation for each assessment date being reduced by all abatements, if any. As used herein, the phrase ''rate for such year'' shall be the rate established by the city or town with respect to the fiscal year commencing during the calendar year for which a return is filed by the corporation.

Any plan for a project may provide that the project may be developed in separate stages, and such stages may be varied from time to time with the approval of the housing board. Whenever a project shall be developed in stages, any excise payable with respect to corporate existence in a calendar year ending before construction of the last stage of the project is completed, shall be computed as though each stage constituted a separate project owned by a separate corporation.

All provisions of chapter sixty-two C relative to the administration of taxes shall, so far as pertinent and consistent, be applicable to the excise imposed by this section. Said excise shall be paid to the commissioner of revenue at the time provided for filing the return required by section twelve of chapter sixty-two C. Said excise shall be distributed, credited and paid to the city or town where the project of the corporation is located.

Real estate acquired by a corporation organized under this chapter by lease from any person other than a housing authority, redevelopment authority, city, town or corporation wholly owned or controlled by a city or town, shall be subject to taxation in the same manner and to the same extent as if such real estate where wholly owned and occupied by a private person; but so long as the period of fifteen years from the organization of such corporation has not expired and the leasehold estate continues to be held by such corporation, all buildings and other things erected by such corporation on, or affixed by such corporation to, any land acquired by such corporation by such lease shall, for the purposes of this chapter and of chapter fifty-nine, be deemed to be tangible personal property of such corporation. Real estate acquired by lease as aforesaid shall be excluded in making determinations and computing the excise under this section, except that the assessed valuation of all buildings and other things erected thereon or affixed thereto on the three assessment dates next preceding acquisition by such lease shall be included in computing the average valuation under clause (b) of the third paragraph of this section.

Notwithstanding any other provisions of this chapter or of any other law, the assessors of the city or town in which a project is to be located may, and upon the request of the housing board they shall determine for the purposes of this section the maximum fair cash value of any proposed project or of any stage or stages thereof. Such determination may be made prior to the construction of the project or of any stage or stages thereof on the basis of the plan for such project, stage or stages. Whenever any such determination shall have been made, the fair cash value of the real estate and tangible personal property of the corporation shall in no event be valued for the purposes of this section in an amount exceeding such maximum fair cash value, except upon a showing that the corporation has acquired real estate or tangible personal property not included in the plan upon which such maximum fair cash value was based, and in such event any such excess valuation shall be limited to the value of such additional real estate and tangible personal property.

All such information, as submitted to the department of revenue and the appellate tax board by such corporation and the assessors of every such city or town, shall be filed with the housing board and in the office of the assessor of the city or town in which the project is located, and, upon request, shall be made available by said department of revenue and by the housing board to any person in accordance with the twenty-sixth clause of section four of chapter seven.

For the purposes of this section, ''gross income'' shall mean payments actually made by persons for the right to reside in or occupy any portion or all of the project and shall not be deemed to include any payments made by any governmental unit to or on behalf of such corporation or to or on behalf of any tenant of such corporation which are in addition to such payments actually made by such tenant.

The fifteen year period of exemption from taxation provided in this section may be extended as herein provided with respect to a project authorized under this chapter for an additional period of time, provided, however, that the original fifteen year period and any additional period shall not exceed, in the aggregate, forty years. The granting of any such extension and the duration thereof shall be based upon the amenities established or to be established in the project area and shall be determined in accordance with rules and regulations from time to time promulgated by the housing board. Said rules and regulations shall detail the nature, quality and quantity of various amenities any one or more of which, if established within the project authorized under this chapter, would significantly contribute to the utility or distinctiveness of the project and shall further stipulate the maximum period and minimum period of extension of exemption from taxation applicable to each such amenity. In determining the duration of the applicable extension period for the purposes of the rules and regulations, the housing board shall consider, among other things, the effect the amenity may have on a project with respect to additional project costs or loss of project revenue.

The schedule of amenities as shall be specified in the rules and regulations, upon which an extension may be granted, shall include, but not necessarily be limited to: (a) housing for persons of low and moderate income; (b) housing or facilities designed for the servicing of the specific needs of handicapped persons; (c) facilities designed for the servicing of the specific needs of learning disabled children; (d) commercial or industrial development which will result in the employment of minority persons or of persons residing in or near the project; (e) restoration or rehabilitation of structures or sites of architectural or historic merit, when such structures or sites are in the National Register of Historic Places or are in the Inventory of Historic Assets of the Commonwealth and when they are certified by the Massachusetts Historical Commission, and when any such registered or certified structures or sites are coupled with the development of facilities which contribute to public understanding the appreciation of their significance; (f) provisions for open space; (g) provisions for recreational or community public facilities; (h) provisions for the incorporation of significant architectural features in the construction and design of the project and (i) provisions for the incorporation of unusual features of construction or design to overcome a factor which contributed to the project being a blighted open area.

The rules and regulations required by this section shall be adopted and may be amended by the housing board only after said board has held a public hearing. Said hearing shall be conducted by the housing board pursuant to the provisions of section two of chapter thirty A except that, and in addition to the notice requirements thereof, the housing board shall, at least thirty-five days prior to the public hearing, send notice of said hearing to: (a) all corporations authorized to undertake a project under provisions of this chapter; (b) any applicant seeking authorization to undertake a project under provisions of this chapter; and (c) the mayor, city council and planning board in cities, and the selectmen and planning board in towns, in which corporations have been authorized to undertake projects or in which applicants seek authorization to undertake projects thereunder. The housing board may rely upon its records in satisfying the notice requirements of this paragraph.

Applications for an extension period shall only be made to the housing board at the time initial authority and approval is sought, except, however, application may be made within ten years after the initial authority and approval is granted provided that such application seeks an extension period based on the establishment of amenities within a portion of a project, the use of which was undesignated at the time of the granting of such initial authority and approval; and excepted further, that in the event of future amendment or change of the rules and regulations promulgated pursuant to this section, application may be made at any time, by a corporation authorized under this chapter, after such amendment or change is in force and effect, provided however, that any such application seeks an extension, the grant of which shall be consistent with any amended or changed rule or regulation then in force and effect.

Applications for an extension period submitted to the housing board pursuant to this section shall be transmitted for public hearing and determination in the same manner as provided for the application for approval of a project under this chapter, provided, however, that if such application for an extension period is submitted as part of an original application for project approval, such application shall be heard and determined in conjunction with the original application.

Subject to the provisions of this section and the rules and regulations of the housing board adopted as provided herein, an application for an extension period may be approved or disapproved, or disapproved with recommended changes which, if made, would warrant approval. In granting approval of such application, the approving authority shall specify the number of years of extension of exemption from taxation granted. If the application is disapproved with recommended changes, the applicant may amend its application for extension of the period of tax exemption in accordance with such suggested changes and resubmit the application as amended to the approving authority. The approving authority may approve or disapprove the application as amended without further public hearing, unless, in its opinion, the proposed changes materially affect the cost of the project, the revenue accruing to the city or town therefrom, or the period of exemption from taxation granted to the project pursuant to this section, in which event the approving authority shall hold a further public hearing in accordance with the provisions of this chapter applicable to an original application.

Any corporation authorized under this chapter proposing (a) a project or portion thereof of housing subsidized by the federal or state government under any program to assist the construction of low or moderate income housing as defined in the applicable federal or state statutes whether built or operated by any public agency or any non-profit or limited dividend organization including a project or portion thereof financed under the provisions of chapter seven hundred and eight of the acts of nineteen hundred and sixty-six, as amended, or (b) a project or portion thereof of low and moderate income housing to be financed in whole or in part by funds made available by the federal or state government or any instrumentality thereof or by any mortgage or mortgage bonds insured or guaranteed by the federal housing commissioner or the administrator of veterans' affairs or any other instrumentality of the federal or state governments shall receive with respect to such projects or portions thereof, an initial fifteen year period of tax exemption as provided by section ten and shall receive an additional period of tax exemption equal to twenty-five years.