Africa's most advanced economy has fallen into recession for the first time in eight years, and pundits are blaming the president.
Zuma turned 75 on Wednesday.
Barclays, HSBC and JPMorgan Chase are among those accused.
The country's finance minister has been summoned by police but says he won't go.
Protesters threw stones and burned tires and police fired rubber bullets and stun grenades, one week into demonstrations.
Thomas Piketty made the point that out of the wealthiest 5 percent of South Africans up to 80 percent are white.