David and Larry Ellison, who created Paramount Skydance with a media merger over the summer, are now poised to bump their all-cash, $30-a-share offer for the owner of Warner Bros., HBO and CNN to as much as $33 a share, according to sources close to the situation.

Global transaction values have risen around 40 per cent to about $4.5 trillion this year, data compiled by Bloomberg show, as companies chase ultra-ambitious combinations, emboldened by friendlier reg...