§ 21.00 Serial bonds. a. Any municipality, school district or district
corporation may issue serial bonds for any object or purpose having a
period of probable usefulness set forth in paragraph a of section 11.00
of this chapter and for which object or purpose it may contract
indebtedness pursuant to section 10.00 of this chapter; provided,
however, that serial bonds shall not be issued by such municipality,
school district or district corporation (1) in those cases in which
provision is made in sections 24.00 and 25.00 of this chapter for the
issuance of tax anticipation notes and revenue anticipation notes to be
issued in anticipation of the collection or receipt of taxes, revenues
or assessments, as the case may be, or (2) in those cases in which
provision is made in section 29.00 of this chapter for the issuance of
budget notes other than paragraph n of such section, or (3) in those
cases in which budget notes have been issued under such paragraph n; and
further provided, however, that nothing contained herein shall prohibit
the issuance of serial bonds by such municipality, school district or
district corporation for the object or purpose specified in subdivision
sixty of paragraph a of section 11.00 of this chapter.

b. Serial bonds shall mature in annual installments. The first
installment shall mature not later than eighteen months after the date
of such bonds or two years after the date of the first bond anticipation
note or notes issued in anticipation of such bonds, whichever is the
earlier, provided, however, that until July fifteenth, two thousand
twenty-four, the first installment shall mature not later than two years
after the date of such bonds or two years after the date of the first
bond anticipation note or notes issued in anticipation of such bonds,
whichever is the earlier. However, if bond anticipation notes are issued
in anticipation of bonds and if a portion of such notes or the renewals
thereof are redeemed from a source other than the proceeds of such bonds
within two years from the date of the first such note or notes and a
further portion thereof shall be so redeemed prior to the termination of
each twelve months' period succeeding the date such original portion was
so redeemed, the first installment of such bonds may, in the
alternative, be made to mature not later than five years from the date
of the first such note or notes.

b-1. Notwithstanding the provisions of paragraph b of this section, if
bond anticipation notes are issued in anticipation of bonds for
assessable improvements and if a portion of such notes or the renewals
thereof are redeemed from a source other than the proceeds of such bonds
within two years from the date of the first such note or notes and a
further portion thereof shall be so redeemed prior to the termination of
each twelve months' period succeeding the date such original portion was
so redeemed, the first installment of such bonds shall mature not later
than twelve months from the last preceding date such portion is so
redeemed.

c. The last installment of serial bonds shall mature not later than
the expiration of the period of probable usefulness of the object or
purpose for which such bonds are issued, as computed from the date of
such bonds or, if bond anticipation notes shall have been issued in
anticipation thereof, as computed from the date of the earliest note or
notes so issued.

d. No annual installment of serial bonds shall be more than fifty per
centum in excess of the smallest prior installment. For the purpose of
the preceding sentence, bond anticipation notes, which are redeemed from
a source other than the proceeds of bonds, shall be deemed to be serial
bonds. Notwithstanding the foregoing, the finance board of any
municipality, school district or district corporation may determine to
issue bonds and provide for substantially level or declining annual debt
service. The determination of whether annual debt service is
substantially level or declining shall not take into account the first
twelve months after issuance to the extent that no provision is to be
made for the payment of principal during such period. If a municipality,
school district or district corporation determines to issue bonds with a
substantially level or declining annual debt service schedule, then the
aggregate amount of debt service payable in each year shall not exceed
the lowest aggregate amount of debt service payable in any prior year by
more than the greater of five percent or ten thousand dollars. For
purposes of this paragraph, debt service shall include all of the
following scheduled to become due: principal, redemption price, sinking
fund installments or contributions, and interest. For purposes of
determining whether debt service is substantially level or declining on
bonds issued with a variable rate of interest pursuant to section 54.90
of this article, the finance board shall estimate the average rate of
interest at which fixed interest rate bonds of the same maturities would
be sold and amortize principal based upon such interest rate assumption.
The estimate by the finance board of such interest rate shall be deemed
final and conclusive. If the finance board of the municipality, school
district or district corporation determines that interest on such bonds
shall be compounded and payable at maturity or prior redemption, such
bonds may be issued only where such finance board has determined to
issue the bonds pursuant to a substantially level or declining annual
debt service schedule unless accrued interest is contributed at least
annually to a sinking fund in accordance with section two of article
VIII of the constitution and the procedures of section 22.10 of this
title. A municipality, school district or district corporation providing
for substantially level or declining debt service may provide for
contracting such indebtedness as serial bonds, as sinking fund bonds, as
term bonds, or as any combination thereof. Term bonds may be issued
under the authority of this paragraph with a stated maturity and a
schedule of mandatory redemptions prior thereto, providing (with other
bonds of the same issue, if any) for substantially level or declining
debt service.

e. Serial bonds shall be redeemed by an annual appropriation.

f. Notwithstanding the provisions of paragraphs b and d of this
section:

1. The first installment of serial bonds issued for the purpose of
providing moneys out of which to make loans to or in aid of
limited-profit housing companies pursuant to article two of the private
housing finance law, or loans to owners of existing multiple dwellings
pursuant to article eight of the private housing finance law, or issued
for the purpose of providing moneys for the effectuating of any urban
renewal program or part thereof pursuant to the general municipal law,
may mature not later than five years after the date of issuance of such
bonds or six years after the date of issuance of the first bond
anticipation note or notes issued in anticipation of such bonds,
whichever is earlier; provided, however, that if the bond anticipation
notes or renewals thereof issued in anticipation of such serial bonds
extend more than five years beyond the original date of such issue,
pursuant to the provisions of paragraph b of section 23.00 of this
chapter, the first installment of such serial bonds may mature not later
than such number of years after the date of issuance of such bonds or
such number of years plus one after the original date of issuance of
such notes, whichever is earlier; and

2. The annual installments of serial bonds issued for such purpose and
for the purpose of providing moneys out of which to make loans to owners
of existing multiple dwellings pursuant to article eight of the private
housing finance law may be computed in such manner that the total of
principal and interest required to be paid in each year beginning with
the year in which the first installment is due, will be approximately
equal to the total of principal and interest required to be paid in each
succeeding year of the period for which such bonds were issued.