Company ABD and Company BCD operate in the same industry and each has a significant...

At the rumour stage (pre-bid), suitable defences are pre-emptive ones:

A – Communicate effectively with shareholders: build support and explain strategy to keep the share price fair and reduce vulnerability.

B – Revalue non-current assets: helps ensure the shares are not undervalued and makes any bid look less attractive.

D – Poison pill: introduce mechanisms (e.g. rights issues to existing shareholders) that make a hostile bid very costly.

C (competition authorities) and E (white knight) are reactive and typically used only once an actual bid has been made.