Santander's acquisition of US-based Webster Financial underscores Chair Ana Botín's ambition for the Spanish bank to become a major player in American retail banking—a move that, some analysts warn, carries execution risks.

Botín, who has maintained Santander's focus on the US despite its more modest profitability there, told analysts that competing on the global stage requires a strong presence in the United States.

"Being one of the most profitable banks in our core geographies is a key objective for Santander, and acquiring Webster allows us to achieve that. Webster gives us the definitive shift we needed in the United States," Botín said on Tuesday.

German López, banking professor at Spain's IESE Business School, noted that Santander's commitment to US expansion is likely to continue in the long term. However, Botín has stated there are no plans for additional acquisitions in the next three years.

"Santander has a global presence (in ten main markets), but she (Botín) believes it is highly relevant for the group's value and reputation to have a meaningful footprint in the United States," López said.

Unlike Spanish rival BBVA, which sold its US retail bank Compass at the end of 2020, Santander has prioritized growth in the United States.

In the US, "you either gain scale to achieve profitability that contributes to the group, or you exit the country," López added.

Barclays analysts indicated that the Webster deal would accelerate Santander's US return on tangible equity (RoTE)—a key profitability metric—to around 18% by 2028, up from the current 10.8%.

The acquisition will also allow Santander to rebalance its loan portfolio toward healthcare services and middle-market lending in the US Northeast.

Botín's strategy aims to position Santander among the ten largest retail and commercial banks in the US by assets, with a combined US balance sheet of about $327 billion. This would reduce the bank's reliance on emerging markets.

Santander shares were down 3.1% at 1554 GMT on Tuesday, after having risen 125% last year.

(Reporting by Jesús Aguado; additional reporting by Emma Pinedo; editing by Elaine Hardcastle; Spanish edition by Benjamín Mejías Valencia)