CA Prob Code Section 5201

(a)

The provisions of Chapter 3 (commencing with Section 5301) concerning beneficial ownership as between parties, or as between parties and P.O.D. payees or beneficiaries of multiple-party accounts, are relevant only to controversies between these persons and their creditors and other successors, and have no bearing on the power of withdrawal of these persons as determined by the terms of account contracts.

(b)

The provisions of Chapter 4 (commencing with Section 5401) govern the liability of financial institutions who make payments pursuant to that chapter.