48 C.F.R. § 604.1601 – Policy.

(c)
(1) Procurement Instrument Identifier (PIID). Uniform numbers shall be assigned to all DOS procurement instruments, domestic and overseas. The numbering system applies to all contracts, purchase orders, and other related instruments, including solicitation documents and delivery orders. This includes instruments executed by DOS contracting officers on behalf of other federal agencies. It does not include requisitions submitted to a contracting activity, or to instruments awarded under Federal assistance arrangements, e.g., grants, cooperative agreements, and loans. Numbers shall be placed in appropriate spaces on government forms and appear on all documentation intended to support official contract files.
(2) Responsibility. Heads of contracting activities are responsible for enforcing compliance with the uniform numbering system. Heads of contracting activities shall develop and maintain a system for assigning and recording contract numbers that conforms to this section.

(3) Instrument identification numbers. A 13-character “alpha-numeric” designator shall be assigned to all DOS procurement instruments. Positions (beginning at the left) one through six shall identify the purchasing office; positions seven and eight, the fiscal year in which the number is assigned; position nine, a symbol designating a type of procurement instrument; and positions ten through thirteen, a four-position serial number.

(i) The first six positions shall commence with “S” to designate a DOS-issued contract. The remaining five characters shall identify the activity preparing the instrument. Domestic and overseas contracting activities shall assign the character codes using the five-digit designator from the listing at http://www.aopeprocurementreports.com/ReportServer_OPEMS2008/Pages/ReportViewer.aspx?%2fDOSReport%2fPostCodeList&rs:Command=Render. DOS organizations not listed shall contact A/OPE for assignment of an office code.
(ii) The seventh and eighth positions shall be the last two digits of the fiscal year in which the number is assigned.

(iii) The ninth position shall be a capital letter assigned to indicate the type of instrument, as follows:

(A) Blanket Purchase Agreement	A
(B) Invitation for Bids	B
(C) Contract (includes letter contracts, contracts incorporating basic agreements and basic ordering agreements)	C
(D) Indefinite Delivery Contract	D
(E) Reserved. Do not use	E
(F) Delivery/Task Order (includes orders placed against all U.S. Government contracts, whether issued by DOS or another agency)	F
(G) Basic Ordering Agreement	G
(H) Basic Agreement	H
(I) Request for Information/Comment	I
(J) Reserved. Do not use	J
(K) Reserved. Do not use	K
(L) Orders under Blanket Purchase Agreements	L
(M) Purchase Order	M
(N) Reserved. Do not use	N
(O) Do not use this letter	O
(P) Personal services contract	P
(Q) Request for Quotations	Q
(R) Request for Proposals	R

(iv)
1. (A) The tenth through thirteenth positions shall be the serial number for the instrument. A separate set of serial numbers may be used for any type of instrument listed in paragraph (c)(3)(iii) of this section. Each series of numbers for the same activity shall begin with the number 0001 at the start of each fiscal year.
(v)
1. (A) The following illustrates a properly configured contract number for the first number assigned to a fiscal year 2015 contract awarded by the Department of State, Embassy Ottawa: SCA525-15-C-0001
2. (B) Use of the dashes to separate the individual elements of the series is optional; however, when reporting individual contract actions to the Federal Procurement Data System (see FAR subpart 6.4), dashes shall not be used.
3. (C) Contracting activities are authorized to use the first digit of the serial number (position 10) to establish discrete series of numbers. For example, the “1000” series may be reserved for Bureau of Consular Affairs requirements (domestic), or the “1000” series may be reserved for Economic section requirements (overseas). Use of discrete series is appropriate generally for activities handling large numbers of transactions and can provide useful management information.

(4) Solicitation amendment and contract modification numbers. Solicitation amendments are to be numbered sequentially, beginning with the alpha designator “A,” e.g., A001. Contract modifications shall also be numbered sequentially, beginning with the alpha designator “M,” e.g., M001.