Prologis said Segro has rejected a sweetened third takeover offer that values the company at £13.5 billion, equivalent to $18.2 billion. The world's largest owner of industrial real estate said Monday that a third offer was rejected on July 17, following a second approach rejected days prior on July 12.

The revised offer includes 0.0890 new Prologis shares for each Segro share, a 6% increase on the initial proposal. It also includes a partial cash alternative of up to £2.7 billion—which equates to 20% of the total offer.

Prologis said based on its stock's closing price of $149.79 on Friday and assuming Segro shareholders opt for the 20% cash component, the third proposal values each Segro share at 993 pence. This is a 33.8% premium to Segro stock's closing price on June 23, before the first offer was made.

Prologis said the third offer is compelling for both sets of shareholders and urged Segro shareholders to encourage their board to recommend the combination.