Banks are economy buildings in Tropico 3 and Tropico 4. A bank can be very useful in developing an island early on. Later, once the island is better established, banks can help line the presidente's wallet or can be put to use in providing financial services to tourists. Banks are also necessary to bribe citizens. If the Tropico 4: Modern Times expansion is installed, banks become obsolete in 1978, when they're replaced by national banks.