Module cusip 

CUSIP — Committee on Uniform Securities Identification Procedures (ANSI X9.6).

A CUSIP is the national securities identifier of the United States and Canada. It is exactly 9 characters in three segments:

  0 3 7 8 3 3 1 0 0
  └────┬────┘ └┬┘ │
       │       │   └ check digit  [8]      one digit [0-9]
       │       └───── issue        [6..8]   two characters [A-Z0-9*@#]
       └───────────── issuer       [0..6]   six characters [A-Z0-9*@#]

• The issuer segment identifies the issuing entity; the issue segment identifies a specific security of that issuer. Both draw from the body alphabet [A-Z0-9*@#] — the digits, the upper-case letters, and the three special characters *, @, #.
• The check digit is the ANSI X9.6 “modulus 10 double add double” of the eight-character body — see crate::checkdigit::cusip_check_digit.

A CINS (CUSIP International Numbering System) number is structurally a CUSIP, computed with the identical check-digit algorithm; it is distinguished only by its first character being a letter, where a domestic CUSIP starts with a digit. Cusip::is_cins reports this, and Cusip::cins_region maps the leading letter to its issuing region.

Cusip::parse enforces every rule: exact length, the body character set, a digit in the check position, and a check digit that is recomputed and verified — never trusted.

References

• ANSI X9.6, Financial Services — CUSIP Numbering System, CUSIP Global Services.

Structs

Cusip

A validated CUSIP (or CINS) number (ANSI X9.6).