Difference between Negotiable Instrument and Financial Asset
CDs are money market instruments and hence are financial asset. There are traditional and negotiable CDs. 

Traditional CDs are like term deposits in banks, and are not tradable. Liquidation before maturity entails penalty charges. 

Negotiable CDs can be traded in the secondary market (referred to as money market). The original holder can 'liquidate' them at prices below the face value in the market. At maturity, the holder of the negotiable CD receives the face value of the security from the issuing bank.