(Bloomberg) -- The recent selloff in UBS Group AG shares underscores the Swiss bank’s challenge to demonstrate its Credit Suisse Group AG acquisition is on solid ground.Most Read from BloombergTruce Talks Drag as Hamas Hits Israel Crossing in Deadly AttackFrance’s Macron Calls for Reset of Economic Ties With ChinaBuffett Praises Apple After Trimming It, Drops Paramount StakeTreasury Rally Risks Running Into a $125 Billion Brick WallXi Begins Europe Tour in Paris as Macron Seeks to Reset TiesResu