[midoridensha]

We already have this: it's called a "brokerage account", or various other names: "mutual fund", "ETA", "company stock", etc.

If you want higher interest (gains) and risk, you buy stock, or a fund.

Finally, if the bank can't move money anywhere, there's no reason for the bank to exist, and there's no way for it to pay interest (in fact, they'd have to charge you to keep your money). The whole way a bank works is by investing your money somewhere, then giving you a fraction of the proceeds (as interest). You seem to not understand at a fundamental level how a bank works.

[brodouevencode]

That's not what I'm suggesting at all. A tiered structure would be normal banking (checking/savings) accounts with differing levels of risk depending on the owner's tolerance and willingness to pay (no/low risk, charged something like 0.5% per year) or be paid (very high risk, and paid to store money there because the bank is lending it out at higher rates).