A bid can be brewing for many months before it is formally announced. Sometimes talks are held and the bidder walks away only to return with new proposals when it feels that the target company will be more receptive.
These informal talks, out of the glare of publicity, can be very useful in determining whether it is worth pursuing a potential bid or in negotiating terms acceptable to all parties.
Time was when companies refused to comment on market rumours but nowadays the Takeover Panel requires them to issue statements when the market gets wind of a potential bid, which is quite often.
Although it is not necessary to comment on a rumour that is utterly without foundation, ...