Nomura Holdings Inc. threatened to seek the immediate repayment of at least €100 million ($136 million) in loans to Espirito Santo Financial Group SA, prompting Monday's sale by the Portuguese company of a stake in Banco Espirito Santo SA, sources said.

Failure to repay the loan could have triggered multiple defaults across companies within the Espirito Santo group, said the sources, who asked not to be identified because they weren't authorized to speak publicly. Espirito Santo Financial Group, one of the companies through which the Espirito Santo family has controlled the bank for most of its 94-year history, Monday sold a 4.99 percent stake in the bank to repay the loan.

The company borrowed money from Nomura to keep its stake in Banco Espirito Santo at 25 percent as the lender sold €1 billion in new stock last month to bolster capital. When shares of the bank plunged 36 percent last week after another company within the Espirito Santo group missed payments on short-term debt, Espirito Santo Financial Group had to either boost the collateral or pay back the loan.