What's going on?

Shares of the eurozone�s largest bank, Santander, rose 2% on Wednesday after it reported strength in Spain, the UK, and Brazil offsetting a weak Argentina.

What does this mean?

Santander�s a pretty global bank, with fingers in many economies� pies. Of those, the UK�s keeping a stiff upper lip, Spain�s sunny, and even Brazil�s starting to move to the music again. Argentina: not so much. The country�s flirting with hyperinflation (when the cost of goods goes up really, really quickly and erodes the value of money) and huge loans � and a currency that�s worth substantially less every day spells bad news for businesses dealing in that currency.

Why should I care?

For markets: The importance of being furthest.

Santander pulls off diversification rather well. With considerable operations all over the world, when one area does poorly (like Argentina), others can pick up the slack � leaving Santander all smiles. Diversification helped HSBC, too. Despite withdrawing from some areas in recent years, the former �world�s local bank� still has a presence in each major financial market, and on Monday it reported profit growth in its latest quarter that was Shang-high.

The bigger picture: International retail therapy.

Diversification is a major reason why big banks often look to grow their investment management businesses. They�re fairly stable and predictable � compared to more volatile stock trading, for example � and help banks to weather any potential economic downturns. Banks typically make decent dough by getting paid a percentage of the amount of money they�re looking after � and they can generally look after (and therefore make) more cash without a lot of extra costs. On Wednesday, Japan�s MUFG agreed to buy the Commonwealth Bank of Australia�s global asset management business for just under $3 billion, while Swiss UBS is keen to expand its own investment management business, too � and it�s also considering buying or partnering with others to get there.