Spain's fifth-biggest bank Sabadell will discuss Thursday whether to shift its registered headquarters away from Catalonia due to leaders' threats to declare independence, a company spokesman said.

The Catalan lender, the second-biggest bank in the north eastern region, convened a board meeting after its stocks plunged as a political crisis between Catalonia and Madrid intensified.

There is a board meeting scheduled for 1500 GMT Thursday and a possible shift of domicile "is one of the subjects that will be discussed and will be decided today," a Sabadell spokesman who asked not to be named told AFP.

The Catalan regional government has said it could declare independence as early as Monday after claiming voters had backed the move in a referendum vote outlawed by Madrid.

The political standoff has dragged Spain into its worst political crisis in decades.

Catalonia accounts for a fifth of Spain's economy.