The Irish exchange is back in the big time, with the US also booming again, writes Kyran Fitzgerald.

Facebook is placing a $19bn (€13.87bn) bet on reaching its next billion mobile users with the acquisition of WhatsApp, the messaging service that lets people send texts, photos, and videos, on their smartphones.

Mobile messaging and call service Viber is being bought for $900m (€657m) by Japanese online retailer Rakuten which is controlled by billionaire Hiroshi Mikitani.