Use of formulas: annual interest securities

June 6, 1983
Use of formulas: annual interest securities. I am writing in response to your letter of June 1, 1983 regarding the appropriate method of calculating yield and dollar price on periodicinterest municipal securities which pay interest on an annual, rather than the more customary semiannual, basis. You note in your letter that Board rule G33 requires the use for purposes of computations of yield and dollar price on such securities of a formula which presumes semiannual payment of interest (i.e., that formula set forth in subparagraph (b)(i)(B)(2) of the rule). You suggest that the rule should be amended to require the use of a formula that recognizes the annual interest payment cycle on the securities.
As I indicated to you in our previous telephone conversation on this subject, the industry has traditionally disregarded the unusual nature of the interest payment cycle on these securities when computing yields and dollar prices on them, and has followed the practice of using the standard formula for computing yield and dollar price on a security paying interest on a semiannual basis for these purposes. As a result of this traditional practice, all of the calculators presently available for use by industry members when computing yields and dollar prices have been designed in accordance with the assumption that all periodicinterest municipal securities pay interest on a semiannual basis; these calculator models cannot be used to compute yields and dollar prices on such securities on any other basis. Therefore, the adoption of a requirement that yields and dollar prices on securities which pay interest on an annual basis be computed by means of a formula which recognizes the annual nature of the interest payment cycle, such as you suggest, would render all of the existing calculator models obsolete, and require that all industry members incur the cost of purchasing new calculator equipment capable of performing such computations (equipment which does not, to my knowledge, exist as of yet).
It is because of the substantial compliance expense that would have been imposed on the industry that the Board declined to adopt a requirement such as you suggest at the time rule G33 was promulgated, even though it recognized that the requirement that was adopted mandated the use of a formula that would produce slightly less accurate results. MSRB interpretation of June 6, 1983.
Day counting: day counts on notes

December 9, 1982
Day counting: day counts on notes. As I indicated in my letter of October 4, your September 27 letter regarding the inclusion on a customer confirmation of information with respect to the day count method used on a transaction was referred to the Board for its consideration at the December meeting. In your letter you noted that Board rule G33 on calculations requires that
[c]omputations under the requirements of [the] rule shall be made on the basis of a thirtyday month and a threehundredsixtyday year, or, in the case of computations on securities paying interest solely at redemption, on the day count basis selected by the issuer of the securities.
You indicated that your bank has recently experienced problems with transactions in municipal notes ("securities paying interest solely at redemption") on which the issuer has selected a day count basis other than the traditional "30/360" basis, with the problems resulting from one party to the transaction using an incorrect day count method. You suggested that this type of problem could be partially alleviated by requiring that a municipal securities dealer selling a security on which an unusual day count method is used specify the day count method on the confirmation of the transaction.
The Board shares your concern that a failure to identify the day count method used on a particular security may subsequently cause problems in completing a transaction. Therefore, the Board believes that the parties to a transaction should exchange information at the time of trade concerning any unusual day count method used on the securities involved in the transaction. Since the party selling the securities is more likely to be aware of the unusual day count, it would be desirable that sellers take steps to ensure that they advise the contraparties on transactions of the method to be used.
The Board does not, however, believe that it would be appropriate to require that this information be stated on the confirmation. The Board reached this determination based on its perception that the space available on the confirmation for the details of the securities description is quite limited and its belief that information regarding the day count method may not be sufficiently material to warrant its inclusion in the securities description. MSRB interpretation of December 9, 1982.
Day counting: securities dated on the 15th of a month

June 2, 1982
Day counting: securities dated on the 15th of a month. I am writing in response to your letter of May 26, 1982 in which you inquire as to the correct day count for calculation purposes on a security which is dated on the 15th of a month and pays interest on the first of a following month. In your letter you pose the example of a security dated on June 15, 1982 and paying interest on July 1, 1982, and you inquire whether the July 1, 1982 coupon on such security should have a value of 15 or 16 days of accrued interest.
As you know, Board rule G33 provides the following formula for use on computations of day counts on securities calculated on a "30/360" day basis:
Number of days = (Y2  Y1) 360 + (M2  M1) 30 + (D2  D1)
In this formula, the variables "Y1," "M1," and "D1" are defined as the year, month, and day, respectively, of the date on which the computation period begins (June 15, 1982, in your example), and "Y2," "M2," and "D2" as the year, month, and day of the date on which the computation period ends (July 1, 1982, in your example). In the situation you present, therefore, the number of days in the period would correctly be computed as follows:
Number of days = (1982  1982) 360 + (7  6) 30 + (1  15)
or
Number of days = (0) 360 + (1) 30 + ( 14)
or
Number of days = 0 + 30 + (  14)
or
Number of days = 16 days
If figured correctly, therefore, the coupon for such a period should have a value of 16 days of accrued interest. If the coupon is for a longer period of time, this particular portion of that longer period would still correctly be counted as 16 days (e.g., the day count on a coupon for the period June 15 to September 1 would correctly be figured as 76 days, consisting of 16 days for the period June 15 to July 1, and 30 days each for the months of July and August).
The error of computing the day count for such a period as 15 days apparently arises from an assumption that, on a security dated on the 15th of a month, accrued interest is owed only for the "second half" of that month. In reality, of course, the 15th of a month is not the first day of the "second half" of that month, but rather is the last day of the "first half" of that month (since a 30day month consists of two 15day halfmonths, the first half being from the 1st to the 15th, and the second half being from the 16th to the 30th). Again, it can clearly be seen that the correct day count for such a period is 16 days. MSRB interpretation of June 2, 1982.