"The majority shareholder of Sberbank is the Central Bank of the Russian Federation, owning 50%+1 voting share of Sberbank's voting shares."
Effectively, the Russian Central Bank controls Sberbank, but ostensibly Sberbank is a private institution. The Podesta Group registered as a lobbyist for Sberbank, which effectively gives the Russian Central Bank a lobbyist in Washington. If the Russian Central Bank had registered directly with the Podesta Group, as the article states the Podesta Group would have to register as agents of the Russian government under the Foreign Agents Registration Act.
The wikipedia page on the Foreign Agents Registration Act (https://en.wikipedia.org/wiki/Foreign_Agents_Registration_Ac...) states:
"...[requires] that agents representing the interests of foreign powers in a "political or quasi-political capacity" disclose their relationship with the foreign government and information about related activities and finances. The purpose is to facilitate "evaluation by the government and the American people of the statements and activities of such persons.""
Arguably, the Podesta Group is not facilitating evaluation of statements its making on behalf of Sberbank, and by extension the Russian Central Bank, because it registered as a lobbyist for a bank controlled by a state-owned bank. The Russians suffered heavy sanctions recently. It doesn't stretch the imagination that the Podesta Group received money from Russia to lobby Washington to drop those sanctions.
As the article states towards the end, if Clinton wins the election, John Podesta stands to gain a position of power in a Clinton administration. If John Podesta benefited from money provided by a foreign government (again, Sberbank is controlled by the Russian Central Bank), then that's a relationship the Clinton campaign needs to explain.