Banco Santander reported an 18 percent increase in net income for 2018 on the back of strong growth in the United States, Brazil and Spain.

Looking at the bank's annual performance, net income reached 7.81 billion euros ($8.93 billion) last year, compared to 6.62 billion euros in 2017.

The Spanish bank also reported Wednesday an increase of nearly 4 percent in net income in the last quarter of 2018 from the previous three-month period — reaching 2.07 billion euros. Shares were marginally higher in morning trade on Wednesday.

Speaking to CNBC, Ana Botin, the executive chairman at the bank, said she is "extremely proud" of the last three years.

"We are extremely proud of what we have achieved these three years, because we have … delivered growth, very few European banks delivered growth. We have delivered more than 20 percent of growth in the top line with profitability and strengthening the balance sheet," she told CNBC's Geoff Cutmore in Madrid.

Botin also said that the bank will keep the current strategy, which is "based on customer loyalty and digital excellence."