LISBON/LONDON (Reuters) – Banco Espirito Santo steadied market jitters about its vulnerability to the troubled business empire of its founding family on Friday but investors are still in the dark about the size of any potential losses. Portugal’s largest listed bank is at the center of a firestorm after concerns about its links to a web of companies controlled by the powerful Espirito Santo clan sparked a rout in global markets this week, prompting some European companies to pull fundraisings and reviving memories of the region’s debt crisis.