(a) Rates—(1)(i) Tier 1 tax. The Tier 1 employer tax rate equals the sum of the tax rates in effect under section 3111(a), relating to old-age, survivors, and disability insurance, and section 3111(b), relating to hospital insurance. The Tier 1 employer tax rate is applied to compensation up to the contribution base described in section 3231(e)(2)(B)(i). The contribution base is determined under section 230 of the Social Security Act and is identical to the old-age, survivors, and disability insurance wage base and the hospital insurance wage base, respectively, under the Federal Insurance Contributions Act.

(ii) Example. The rule in paragraph (a)(1)(i) of this section is illustrated by the following example.

(2)

(i) Tier 2 tax. The Tier 2 employer tax rate equals the percentage set forth in section 3221(b) of the Internal Revenue Code. This rate is applied up to the contribution base described in section 3231(e)(2)(B)(ii).

(ii) Example. The rule in paragraph (a)(2)(i) of this section is illustrated by the following example.

(3) Supplemental Annuity Tax. The supplemental annuity tax for each work-hour for which compensation is paid by an employer for services rendered during any calendar quarter by employees is imposed at the tax rate determined each calendar quarter by the Railroad Retirement Board. See also §31.3221-3.

(b)

(1) Computation. The employer tax is computed by multiplying the amount of the compensation with respect to which the employer tax is imposed by the rate applicable to such compensation, as determined under paragraph (a) of this section. The applicable rate is the rate in effect at the time the compensation is paid. For rules relating to the time of payment, see §31.3121(a)-2(a) and (b).

(2) Example. The rule in paragraph (b)(1) of this section is illustrated by the following example.

[T.D. 8582, 59 FR 66190, Dec. 23, 1994]