(a) The rate of contribution payable by an employer eligible for an adjusted rate with respect to the calendar year beginning 1984, and each calendar year thereafter, shall be adjusted between a minimum rate of three-tenths of one per centum (0.3%) and a maximum rate of eight and five-tenths per centum (8.5%) for 1984, eight and eight-tenths per centum (8.8%) for 1985, nine and two-tenths per centum (9.2%) for 1986 through 2012, eight and seven-tenths per centum (8.7%) for 2013 through 2016, nine and five one-hundredths per centum (9.05%) for 2017 and eight and ninety-five one-hundredths per centum (8.95%) for 2018 and thereafter which shall be the aggregate of three factors:

Group 1 shall consist of those employers who have paid contributions under this act for one or more quarters in the twelve-month period ending on the computation date for the year for which the rate is applicable and have also paid contributions under this act for one or more of the four completed calendar quarters immediately preceding such twelve-month period.

Group 2 shall consist of employers who have paid contributions under this act for one or more quarters in each of the two twelve-month periods ending on the computation date for the year for which the rate is applicable and have also paid contributions under this act for one or more of the four completed calendar quarters immediately preceding such two twelve-month periods.

Group 3 shall consist of employers who have paid contributions under this act for one or more quarters in each of the three twelve-month periods ending on the computation date for the year for which the rate is applicable and have also paid contributions under this act for one or more of the four completed calendar quarters immediately preceding such three twelve-month periods.

(d) An employer's Benefit Ratio Factor shall be computed on the basis of the following formula:

to a tenth of a per centum, rounding all fractional parts of a tenth of a per centum to the nearest tenth of a per centum. No Benefit Ratio Factor shall be more than five per centum (5%) nor less than zero per centum (0%).

in which factor “Bdr” equals the aggregate of (1) all benefits paid but not charged to employers' accounts, plus, (2) all benefits paid and charged to inactive and terminated employers' accounts, plus, (3) all benefits paid and charged to accounts of active employers for the preceding year to the extent such benefits exceed the combined amount of contributions payable by such employers on the basis of the Benefit Ratio Factor and the Reserve Ratio Factor. Factor “Dcr” equals the aggregate of (1) interest credited to the Unemployment Compensation Fund, plus, (2) amounts transferred from the Special Administration Fund and the Debt Service Fund to the Unemployment Compensation Fund, plus, (3) refunds of benefits unlawfully paid, plus, (4) amounts credited to the Unemployment Compensation Fund by the Federal Government other than by loan, except that any amount credited to this Commonwealth's account under section 903 of the Federal Social Security Act² which has been appropriated for expenses of administration shall be excluded from the amount in the Unemployment Compensation Fund in the computation of the “Dcr” factor. Factor “Wt” equals all wages subject to the law up to the limitation described in section 4(x)(1)³ paid by all employers. Each item in each factor shall be computed with respect to the twelve-month period ending on the computation date: Provided, That should the computed State Adjustment Factor for any year exceed the maximum rate allowed under this section, such excess over the maximum rate shall be added to the computed State Adjustment Factor for the following year or years.

(f) An employer whose reserve account balance is adjusted after January 1, 1980 in accordance with the provisions of section 302(c) of this act⁴ shall not be eligible for a reduced rate of contributions under the provisions of this act for the three consecutive calendar years following the computation date with respect to which the application for adjustment was made and shall pay contributions at the maximum rate specified under subsection (a) of this section and sections 301.2 and 301.6⁵ for three years. In the event an employer shall file one or more subsequent applications for adjustment, the provisions of this subsection shall apply to each such application.

(f.1) Notwithstanding any other provisions of this act, employers who elected to have their negative reserve account balance adjusted for taxable years 1978, 1979 or 1980 will be liable for contributions at the maximum rate specified in section 301.1 and as determined under sections 301.2 and 301.3.⁶

(g) Wages paid to employes of construction contractors pursuant to a contract or subcontract entered into before July 1, 1983 for the construction, reconstruction or remodeling of structures where the contract or subcontract is either at a fixed price not subject to change or modification or entered into pursuant to the obligation of a formal written bid which cannot be altered or withdrawn shall continue to be subject to the employer's assigned tax rate and the taxable wage base for 1983. This subsection shall not apply to any year following calendar year 1984. No rate assigned any employer who receives a rate on the basis of employment and wages to which this subsection applies shall be less than two and seven-tenths per centum (2.7%) for calendar year 1983 or 1984 and no rate shall be less than five and four-tenths per centum (5.4%) for calendar year 1985 and thereafter.