These were introduced in May 2004 by all old (EU 15) Member States (except Ireland, Sweden and the UK which opened up their labour markets without restrictions to nationals of the new Member States) on workers from the eight new EU Central and Eastern European countries.
Papildu līdzekļi vajadzīgi investīcijām citos kopīgas nozīmes projektos — tās galvenokārt nodrošinās enerģijas tīklu operatori un privāti uzņēmumi, un dažos gadījumos papildinās ES finansējums vai aizņēmumi.