Christian Dior - Outlet Palermo
Located in Palermo, very close to the Botanical Gardens. The exact address is Lafinur 3057, Ciudad de Buenos Aires.

Christian Lacroix - Outlet
Also in Palermo, close to the ACA on Godoy Cruz. The exact address is Juan F. Seguí 4662, Ciudad de Buenos Aires.

Yves Saint Laurent - Outlet
Address: Alsina 1479, Ciudad de Buenos Aires.

Please note, the above addresses seem to be current as this post is written, but locations do change from time to time. Of the three designers posted above, Christian Lacroix will probably have the least formal wear (designs will be more modern). For banking/law firm type clothes, its probably not your best choice, although its still worth shopping around.

These outlet stores will usually carry geat from the previos 2-3 seasons and also have some overstock items of the current collections.

Hope this helps!!!

Cheers,
Alex