If an institutional wants a big slice of a very yummy cake....often they have to pay a premium to the share price of today. If you want to buy 100 million shares....you won't be able to buy them on market at todays price...AVZ is hot, and if you want a slice....bloody pay up! AVZ doesn't need any cash urgently...so my guess, it's a premium price for the cake.
GL with a positive announcement