According to eIDAS (Electronic identification and trust services), a certificate for a legal person need the new directory attribute "organizationIdentifier" in its Subject DN, to identify the organization (cf. ETSI 319-412-1, § 5.1.4).

Action:

• add the attribute type "organizationIdentifier" (OID: 2.5.4.97)

Remarks:

• ETSI 319-412-1, v1.0.0 (2015-06) in DRAFT,
• the ETSI final documents are planed for 2016 Q1, but ITU-T X.520 had been published in October 2012,
• no short name is defined by X.520 for "organizationIdentifier" --> I propose "ORGID" (because "OID" is not a good choice!) [to discuss in comments].

— References

ITU-T X.520 - ITU-T Recommendation database
http://www.itu.int/itu-t/recommendations/rec.aspx?rec=X.520
--> § 6.4.4 Organization Identifier

ETSI EN 319 412-1 - Electronic Signatures and Infrastructures (ESI); Certificate Profiles; Part 1: Overview and common data structures
http://www.etsi.org/deliver/etsi_en/319400_319499/31941201/01.00.00_20/en_31941201v010000a.pdf
--> § 5.1.4 Legal person semantics identifier

Directory Attribute Type: organizationIdentifier
http://oid-info.com/get/2.5.4.97

{joint-iso-itu-t(2) ds(5) attributeType(4) organizationIdentifier(97)}