<p>Portugal's central bank says an offer from U.S. private equity firm Lone Star is the most promising bid to buy Novo Banco, the so-called good bank salvaged by the Portuguese government from the collapse of major lender Banco Espirito Santo.</p>
<p>The Bank of Portugal said late Wednesday it has invited the fund, based in Dallas, Texas, to "deepen negotiations" over the possible purchase, though it said rival bidders have expressed a willingness to improve their offers and would not be excluded.</p>