I know enough about Grudinin, to not to buy the lies that are spread about him.
Yes he is a wealthy man and he even keeps his money in German/Austrian banks, which gives Putin and Co a chance to point a finger at him, howling happily "see, he is no different from us."
Nice try, but I side with Grudinin, when he said that "if you want to run business honestly in Russia, you can't trust Russian banks."
With other words, he is no fool and he understands how the "new Russians" gang made THEIR money, while being protected by the Western banking system.
But when HE goes the same rout, while staying independent from the well-connected gang, and challenges them in politics, the propaganda machine immediately uses it for the smear campaign, knowing how sensitive Russian public is to the whole "oligarchs/overseas accounts" issue.
(All while Putin positions himself as he has nothing to do with it, of course.)
This is precisely the good old song of Visotsky, the lyrics that describe situation up to a "t."
"A Parable of Truth and Lie"
( Not sure how good translation is, but it's at least something...)
In fact, the whole Putin's Russia is described rather well by this song.
The devil is in details as they say.