Securities
Bonds, notes, shares, warrants, certificates - negotiable investments[1] that can be bought and sold freely in the market between willing counterparties without the knowledge or consent of the issuer. To "securitise" an income stream or asset is to convert it into such a form.
- ↑ I say investments not instruments because a cheque is a negotiable instrument, and I don't think you would commonly call that a security.