Wilful defaulter prohibition bars persons categorized as wilful defaulters from making open offer announcements under takeover rules. The amendment defines 'wilful defaulter' as a person categorized by banks or financial institutions under RBI guidelines, including persons whose director, promoter or partner is so categorized, and provides that no wilful defaulter shall make a public announcement of an open offer or enter into transactions attracting the obligation to make such an announcement, except that a wilful defaulter may make a competing offer under the applicable competing offer provision.