Hochtief, a listed German construction company controlled by Spain's ACS, today is expected to make a takeover bid for Spanish toll road operator Abertis, which already had agreed to be acquired by Italy's Atlantia for around $35 billion (including debt), per Reuters.

Why it matters: Because Atlantia-Abertis already was the largest merger announced in 2017, intended to create the world's largest toll-road operator. A counter-bid from Hochtief/ACS likely would be a bit richer, and certainly would delay a deal close (no matter the ultimate winner).

Next: Expect Atlantia to strongly consider topping any rival offer.

More from Reuters: "Sources have said that the prospect of a foreign takeover of Abertis, which manages politically sensitive concessions for motorways across Spain, has raised some concerns in Madrid." — Reuters