(Sharecast News) - Banco Santander unveiled an 18% jump in its full-year 2018 attributable profits to €7.8bn thanks to a strong performance in the US, Spain, Brazil and Mexico, which easily offset weakness in the UK and Argentina, two of its most important markets.According to FactSet, analysts had been calling for a slightly lower profit of €7.6bnAlso at constant exchange rates, the Spanish lender reported a 34% increase in attributable profits for the last quarter of 2018 (€2.07bn) in comparison to the year earlier period.Underlying profits meanwhile were ahead by 5% to €2.02bn and by 12% at constant FX."Strong" customer revenues in several markets, like Brazil, Spain, Mexico and the United States, and improvements in credit quality offset the impact of the fall in value of some currencies against the euro, such as the Argentine peso.Earnings for 2018 increased by 7% in the year, to €8.06bn, and the bank stressed it had achieved its goal of reaching double-digit growth in earnings per share (EPS) in 2018, with an increase of 11.2%, to €0.449.The number of linked clients, those who consider Santander their main bank, increased by 2.6m to 19.9m, while the total number of customers increased by 11m over the year just ended to hit 144m.Santander chairwoman, Ana Botin, said that "2018 has been an excellent year for the group, we have successfully completed our strategic plan for three years and to achieve this, our focus has been on gaining the trust of our clients and in the transformation. Thanks to this, we continue as one of the most profitable and efficient banks in the world among our competitors."Botin also expressed confidence that Santander could "continue growing organically" adding that management would update markets on the new strategic plan next April. She also highlighted the importance of Latin America as "the group's growth engine, with good progress, especially in Brazil and Mexico."In Brazil, Santander's largest market, attributable profits rose by 2% to €2.61bn (22% at constant euros). It was a similar story for Mexico, with net profit up by 7% in the fourth quarter to €760m.In Argentina on the other hand, adjustments to profits and the balance sheet linked to high inflation meant that attributable profits plummeted 77% to €84m, or by 54% at constant exchange rates.In the UK, attributable full-year profits fell by 9% to €1.36bn because of increased operating costs due to investments in digital transformation and regulatory projects, among other things."While a highly competitive landscape placed pressure on revenues, credit quality remained extremely strong, with a cost of credit at 0.07%."