0854 GMT - A tie-up between BASF and Evonik could prove complicated, analysts at Bernstein write in a note. German chemicals giant BASF said last week it had opened talks with its smaller rival, noting its interest in acquisitions that fuel growth. "There is a price / synergy level where the logic for this transaction could be compelling," Bernstein says. But a takeover of Evonik would skew BASF's assets further toward Europe and a combined group would likely trade at a lower multiple than BASF alone, the brokerage estimates. "We have our reservations about a combined BASF-Evonik equity story, as we believe BASF can extract substantial value from their existing assets and there is no guarantee a transaction goes ahead," Bernstein says.