Interest rate table library entries allow you to modify historical interest rates in various ways and then reference the resultant rates to calculate Annuity Factors, Interest Factors, Late Retirement factors, Actuarial Equivalence, and cash balance component Interest Crediting.  

Name is a text field in which to enter a description of the Interest Rate Table. This may be any descriptive phrase, including spaces.

Historical Interest Rate Table allows you to select a historical interest rate table from the text (.txt) or comma separated values (.csv) files in the folder that’s specified as the HIRTdir parameter of the ProAdmin.INI file.  There are four types of interest rates tables that ProAdmin recognizes: 

The Type drop-down filters the source tables available for selection to only those of the designated table type.  The choices available are: ALL, SPOT, FLAT, PBGC and DUR. This is a simple filter to aid in finding a source table; it does not affect any features for the selected table.

The View Source button adjacent to historical interest rate table selection displays the selected table before any adjustments have been applied. 

The Only use checkbox is available for spot-style tables and PBGC-style tables, but with different options.  If the table selected is a Spot-style table, you can choose to Only use initial spot rates, second spot rates or third spot rates, indicating that, for Spot-style tables, only the selected first, second or third (segment) rate at each date will be used and the other (segment) rates will be ignored. If the table selected is a PBGC-style table, you can choose to Only use immediate rates, indicating that, for PBGC-style tables, the three deferral rates will not be determined and only the immediate rates will be used. 

If checked, the ​Freeze rates as of (mm/yyyy) ​box indicates that the calculated plan rates will be frozen starting at the month specified. 

If checked, the Average Rates box indicates that rates from the historical interest rate table will be a averaged based on the specified parameters. Enter the Averaging Period Months to indicate the number of months over which interest rates will be averaged. This should be entered as an integer. Select the Start of Averaging Period to identify the first month of the averaging period. The value for all months from this month to the end of the averaging period will be the average amount for the period. Use the Averaging approach to set the averaging approach to be used. If Arithmetic is selected, a simple average of rates during the period is used. If Geometric is selected, the average rates during the period are defined as -1 plus the nth root of (1+r1) (1+r2) ... (1+rn), where n is the averaging period.

If rates are averaged, the order of operations is as follows:

1.	Calculate the average rate associated with each date on a rolling basis. So, for example, if the Averaging Period is 3 months and the Start of Averaging Period is October, the October, 2018 rate will be set to the average of the actual August -  October, 2018 rates, and the November, 2018 rate will be set to the average of the actual September-November, 2018 rates.
2.	If there's a Lookback period, move the rates the requested number of months.  If the lookback period is 2 months in our example, the December, 2018 rate would now be the average of the actual August-October, 2018 rates.
3.	Freeze the rates based on the Stability period.  If the stability period is a year, starting with January in our example, the 2019 rate would be the average of the actual September-November, 2018 rates.

If checked, the Increase rates by box increases the averaged interest rates by the amount entered, such as .015 for 150 basis points. Valid values are between -0.1 and 0.1.

If checked, the Multiply rates by box multiplies the averaged and increased rate by the amount entered, such as 1.05 for 105%.  

If checked, the Minimum rate box will ensure that rates do not fall below the specified rate.  This is particularly useful if increase rates are set to a negative number. 

If checked, the Maximum rate box will ensure that rates do not go above the specified rate.

If checked, the Apply rounding rule box indicates that the adjusted rate should be rounded according to the specified parameters. Enter the Amount, as a decimal value, to which the rate should be rounded. A value of .0025, for example, indicates that rates should be rounded to 25 basis points. Valid values fall within the range 0.0000001 to 0.01. Also select the Direction that the rate should be rounded to, where the choices are up, down, or to the nearest multiple of the rounding rule amount.

The Lookback period sets the number of months back from the beginning of the stability period that the interest rate will be determined. For example, if the stability period is set to a year starting in January and the lookback period is set to 2, the stability rate will be the otherwise rate as of prior November, and that rate will remain in effect until the next January.  Valid values for the lookback period are between 0 and 12.

Use the Stability period radio buttons to indicate the period of time for which rates will be stable.  Select Month if rates will remain stable for a month at the rate applicable to the beginning of the month. Select Quarter, starting with if rates will remain stable for a three months at the rate applicable to the specified month which begins the quarter. The drop down sets the month starting with which rates are stable. Select Half-year, starting with if rates will remain stable for six months at the rate applicable to the beginning of the six month period that starts with the specified month. Select Year, starting with if rates will remain stable for a year at the rate applicable to the specified month which begins the year. 

The View button in the bottom left corner of the dialog box displays the selected table after all (except zero minimum) adjustments have been applied.  The adjustments are done from top to bottom.