On registering each participant obtains a Participant Identification Code (PIC, 9-digit number) which acts as its unique identifier in the Participant Register. A participant needs to register only once – the information provided can be further updated or re-used by the participant in other European Commission's calls for tenders or calls for proposals. 

At any moment during the procurement procedure the Research Executive Agency Validation Services (hereafter the EU Validation Services) may contact the participant and ask for supporting documents on legal existence and status [and financial capacity]. The requests will be made through the register's messaging system to the e-mail address of the participant's contact person indicated in the register. It is the responsibility of the participant to provide a valid e-mail address and to check it regularly. 

The documents that may be requested by the EU Validation Services  are listed in the EU Grants and Tenders Rules on Legal Entity Validation, LEAR appointment and Financial Capacity assessment. 

##   Please note that a request for supporting documents by the EU Validation Services  in no way implies that the tenderer has been successful. 

## 2.4. Ways to submit a tender 

Economic operators can submit a tender either as a sole tenderer or as a group of tenderers. In either case subcontracting is permitted. 

In order to fulfil the selection criteria set out in Section 3.2 the tenderer can rely on the capacities of subcontractors or other entities (not subcontractors). 

The role of each entity involved in a tender (hereafter referred to as involved entity ) must be clearly specified: sole tenderer, member of a group or Group leader, subcontractor or an entity on whose capacities the tenderer relies to fulfil the selection criteria$^{20}$. This applies also where the involved entities  belong to the same economic group. 

Tenderers are invited to apply in English to facilitate the selection process. 

## 2.4.1. Joint tenders 

A joint tender is a situation where a tender is submitted by a group (with or without legal form) of economic operators regardless of the link they have between them. The group as a whole is considered a tenderer$^{21}$. 

All members of the group assume joint and several liability towards the Contracting authority for the performance of the contract as a whole. 

