N.Y. Comp. Codes R. & Regs. tit. 20, § 7-2.6
Tax Law, § 213-a(g)
If a taxpayer is required to make a declaration of estimated tax pursuant to section 7-2.1 of this Subpart and a short taxable year is involved, a declaration for the fractional part of the year is required. No declaration is required if the short taxable year is a period of five months or less.