Updated from Sunday, Oct. 13Spain's Banco Santander ( STD) is in advanced talks to acquire full control of Sovereign Bancorp ( SOV), according to a published report. The two sides were in deep negotiations and hoped to complete a deal by Monday, the Wall Street Journal reports, citing people familiar with the matter. Details of the transaction weren't clear, but Santander was expected to pay roughly Sovereign's stock price on Friday of $3.81. That would value Sovereign at about $2.53 billion. Sovereign approached Santander late last week. Sovereign shares were up a penny at $3.82 in recent trading Monday morning. Santander has been considered a potential buyer of Sovereign, which has $79 billion in assets and 750 branches in the northeastern U.S., ever since the Spanish bank got a 24.9% stake in Sovereign three years ago and three seats on its board, according to the Journal. Under terms of that agreement, Santander was entitled to bid for Sovereign after May 31, 2008, but the Spanish bank had to offer at least $40 a share. That provision was later amended to $38 a share. With Sovereign's stock price down by more than 60% so far this year, the company's directors appeared likely to waive those conditions, people close to the talks said, the Journal reports.