Meaning he keeps it all at his place, or somewhere super top secret?  Former teammate Casey Jacobsen talks about it all in an online interview.  From SLAM:

It’s nearly impossible to explain the weirdness that is Darko, but he told me one time that he did not keep his money in any bank, nor did he invest in stocks or bonds. “I just keep it,” he told me and then turned away. Looking back, I should have asked a follow-up question. I don’t know if I believe him, but he was making over $6 million that season. That’s a lot of cheddar to stash underneath a mattress! On another note… that was easily the longest conversation we ever had, and that was how he preferred it.

So perfect in so many ways.

[SLAM]