They may buy bonds or something like that.

For a 20% return in a year?

The numbers given have to be incorrect.

Oh yeah I wasn't taking OPs number at face value

probably 2%, not 20%.

Yielding a yearly 20%?

If anyone knows of _any_ investment yielding a yearly 20% reliably, I'd certainly be interested. If Starbucks figured that out, I don't know why they're bothering making coffee.