SEDOL stands for Stock Exchange Daily Official List, a list of security identifiers used in the United Kingdom and Ireland for clearing purposes. The numbers are assigned by the London Stock Exchange, on request by the security issuer. SEDOLs serve as the NSIN for all securities issued in the United Kingdom and are therefore part of the security's ISIN as well.

[edit] Description

SEDOLs are seven characters in length, consisting of two parts: a six-place alphanumeric code and a trailing check digit. SEDOLs issued prior to January 26, 2004 were composed only of numbers. For those older SEDOLs, those from Asia and Africa typically begin with 6, those from the UK and Ireland (until Ireland joined the EU) typically begin with 0 or 3 those from Europe typically began with 4, 5 or 7 and those from the Americas began with 2. After January 26, 2004, SEDOLs were changed to be alpha-numeric and are issued sequentially, beginning with B000009. At each character position numbers precede letters and vowels are never used. All new SEDOLs, therefore, begin with a letter. Ranges beginning with 9 are reserved for end user allocation.

The check digit for a SEDOL is chosen to make the total weighted sum of all seven characters a multiple of 10. The check digit is computed using a weighted sum of the first six characters. Letters have the value of 9 plus their alphabet position, such that B = 11 and Z = 35. While vowels are never used in SEDOLs, they are not ignored when computing this weighted sum (e.g. H = 17 and J = 19, even though I is not used), simplifying code to compute this sum. The resulting string of numbers is then multiplied by the weighting factor as follows:

 First   1 Second  3 Third   1 Fourth  7 Fifth   3 Sixth   9 Seventh 1 (the check digit) 

The character values are multiplied by the weights. The check digit is chosen to make the total sum, including the check digit, a multiple of 10, which can be calculated from the weighted sum of the first six characters as (10 − (weighted sum modulo 10)) modulo 10.

For British and Irish securities, SEDOLs are converted to ISINs by padding the front with two zeros, then adding the country code on the front and the ISIN check digit at the end.

[edit] Example

BAE Systems: 0263494

The checksum can be calculated by multiplying the first six digits by their weightings:

(0×1, 2×3, 6×1, 3×7, 4×3, 9×9) = (0, 6, 6, 21, 12, 81)

Then summing up the results:

0 + 6 + 6 + 21 + 12 + 81 = 126

The check digit is then calculated by:

(10 − (126 modulo 10)) modulo 10 = (10 − 6) modulo 10 = 4

[edit] In Delphi

 function GetSedolCheckDigit(const BaseSedol: string): Integer; const   Weights: array[1..6] of Integer = ( 1, 3, 1, 7, 3, 9 ); var   i, d: Integer; begin   if Length(BaseSedol) <> 6 then     raise Exception.Create(       'SEDOLs without a check-digit must be six characters long');   Result := 0;   for i := 1 to 6 do begin     case BaseSedol[i] of       '0'..'9': d := Ord(BaseSedol[i]) - Ord('0');       'A'..'Z': d := Ord(BaseSedol[i]) - Ord('A') + 10;       else          raise Exception.Create(           'SEDOLs must have only digits and uppercase letters');     end;     Inc(Result, d * Weights[i]);   end;   Result := (10 - (Result mod 10)) mod 10; end; 

[edit] In J

(other formulations as possible; some twice as fast^[1]):

    sn   =.  '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ'  NB.  SEDOL numerals    acs  =:  (10 | 1 3 1 7 3 9 +/@:* -)&.(sn i. |:)  NB.  Checksum 

[edit] In Perl

 my @weights = (1, 3, 1, 7, 3, 9);   sub sedol_check_digit {     my ($sedol) = @_;     die "invalid SEDOL format: `$sedol'\n"         if $sedol !~ /^[0-9A-Z]{6,7}$/;       my @chars = split //, $sedol;     my $sum = 0;     for my $i ( 0 .. $#weights )     {         my $char = $chars[$i];         my $value = $char =~ /\d/             ? $char             : ord($char) - ord('A') + 10;           $sum += $value * $weights[$i];     }       return (10 - ($sum % 10)) % 10; } 

[edit] In Python

 import string   # constants sedolchars = string.digits + string.ascii_uppercase sedol2value = dict((ch, n) for n,ch in enumerate(sedolchars)) for ch in 'AEIOU':     del sedol2value[ch]   sedolchars = sorted(sedol2value.keys()) sedolweight = [1,3,1,7,3,9,1]   def check(sedol):     return len(sedol) == 7 and \            all(ch in sedolchars for ch in sedol) and \            sum( sedol2value[ch] * sedolweight[n]                 for n,ch in enumerate(sedol) ) % 10 == 0   def checksum(sedol):     tmp = sum( sedol2value[ch] * sedolweight[n]                for n,ch in enumerate(sedol[:6]) )     return sedolchars[ (10 - (tmp % 10)) % 10]   sedol = '0263494' print sedol, checksum(sedol) 

[edit] In Visual Basic

 Option Explicit   Public Function getSedolCheckDigit(str As String) As Integer     ' calculates the final digit of a six digit sedol code using the algo described on wikipedia     If Len(str) <> 6 Then         getSedolCheckDigit = "Six chars only please"         Exit Function     End If     Dim mult(6) As Integer     mult(1) = 1: mult(2) = 3: mult(3) = 1: mult(4) = 7: mult(5) = 3: mult(6) = 9     ' didn't use Array() to avoid Option Base problems     Dim i, total As Integer     Dim s As String     total = 0     For i = 1 To 6         s = Mid(str, i, 1)         total = total + IIf(IsNumeric(s), Val(s), Asc(s) - 55) * mult(i)     Next     getSedolCheckDigit = (10 - (total Mod 10)) Mod 10 End Function   Public Function IsSedolValid(ByVal Sedol As String) As Boolean    IsSedolValid = (getSedolCheckDigit(Left$(Sedol, 6)) = CInt(Right$(Sedol, 1))) End Function 

[edit] In T-SQL

 CREATE FUNCTION [dbo].[fn_IsSEDOLValid] ( @sSEDOL  AS  NVARCHAR(10)) -- Author: Abul Hasnat -- Description: SEDOL Validation code in TSQL RETURNS BIT AS BEGIN   -- Declare the return variable here   DECLARE @ResultVar AS BIT         , @i	     AS	INT         , @total     AS	INT         , @s	     AS	NVARCHAR(10)         , @tmpStr    AS	NVARCHAR(10)         , @tmpDigit  AS	INT     DECLARE @Multi	AS	TABLE(ID INT,IDX INT)     --Populate TempTable   INSERT INTO @Multi (ID,IDX) VALUES (1,1)   INSERT INTO @Multi (ID,IDX) VALUES (2,3)   INSERT INTO @Multi (ID,IDX) VALUES (3,1)   INSERT INTO @Multi (ID,IDX) VALUES (4,7)   INSERT INTO @Multi (ID,IDX) VALUES (5,3)   INSERT INTO @Multi (ID,IDX) VALUES (6,9)   -- Check Given SEDOL Code is 7 Digit   IF(LEN(@sSEDOL)<>7)     BEGIN       SET @ResultVar = 0     END   ELSE     BEGIN       -- CHECK last digit is number       IF(ISNUMERIC(SUBSTRING(@sSEDOL,LEN(@sSEDOL),1))=1)         BEGIN  	  SET @total = 0 	  SET @tmpStr = SUBSTRING(@sSEDOL,1,6) 	  SET @i=1 	  WHILE (SELECT @i) <=6 	    BEGIN 	      SET @s = SUBSTRING(@tmpStr, @i, 1)               SET @total = @total + (SELECT CASE ISNUMERIC(@s) WHEN 1  THEN @s ELSE (ASCII(@s) - 55) END)* (SELECT IDX FROM @Multi WHERE ID=@i) 	      SET @i= @i +1 	    END 	  -- Get Check Digit 	  SET @tmpDigit = (10 - (@total % 10)) % 10 	  -- Match Check Digit for SEDOL 	  IF (SUBSTRING(@sSEDOL,LEN(@sSEDOL),1) = @tmpDigit) 	    SET @ResultVar = 1 	  ELSE 	    SET @ResultVar = 0 	END       ELSE 	BEGIN  	  SET @ResultVar = 0 	END    END    -- Return 1 if valid otherwise Return 0 as False    RETURN @ResultVar END GO 

[edit] Notes

[edit] External links

• London Stock Exchange
• SEDOL Master File Technical Spec. Word Document (see section 7)
• SEDOL on rosettacode.org
• Sedol validation routines for Informatica, Talend and Pentaho