ultra vires and irregular acts A distinction must be made between acts which are ultra vires and those for the validity of which certain formalities are necessary. In the latter case, persons dealing without notice of any informality are entitled to presume omine rite esseacta (all acts have been done rightly.). Accordingly, a company which, possessing the requisite powers, so conducts itself in issuing debenture as to represent to the public that they are legally transferable, cannot set up any irregularity in their issue against an equitable transferee for value who has no reason to suspect it.