Spain's BBVA on Thursday posted a 90 percent fall in fourth quarter net profit against the same period a year earlier after a 1.1-billion-euro ($1.4 billion) writedown on its Telefonica stake.

Speaking to CNBC on Thursday, Carlos Torres Vila, chief executive officer of BBVA, explained the reason for the 90 percent drop, saying it was related to stock price movements. He said the capital position of the bank remains intact.

"There is really no change in our strategy with our Telefonica stake, it is only an accounting impact," Vila told CNBC.