"I doubt that logic applies if you buy additional shares after accepting the offer though - there are various clauses in the offer booklet saying (in effect) that increases in your holding don't count. For example, in Section 9.1 (e)"
The Hochtief bidders statement doesn't, as far as I can see, directly address the issue of acquiring additional shares after the offer period commences, but from my reading of the statement I do not come to the same conclusion as you. Section 9.1 (e) seems to be only applicable to newly acquired holdings in Leighton (acquired after the offer period commences) that would leave an unmarketable quantity of Leighton shares if the offer was accepted for that holding. Since Hochtief will pay $22.50 for ALL of your shares instead of just 3/8s should the latter conversion leave you with an unmarketable quantity of Leighton shares (<$500), I think it is just trying to protect itself from those who would deliberately buy parcels of LEI after the offer period commences knowing full well that would put them in an unmarketable parcel situation should they accept the offer. In other words, go out an buy LEI on market at say $20.43 (today's close), then accept the offer in relation to those shares knowing full well that you would end up with an unmarketable parcel after acceptance so that Hochtief is forced to buy all (instead of just 3/8s) of your new holding at $22.50. You would be guaranteeing yourself a profit with no risk.
I may be wrong, but I think that is what it is trying to protect itself against.
LEI Price at posting:
$20.43 Sentiment: None Disclosure: Held