Zero Knowledge Proof - Offline Data
You would need something to prevent do what you would do if those balances were what you said they are from causing the verifier to accept.

That main way of getting that is the prover and verifier both have a statistically binding encapsulation for each of those balances, as described in the paper Improved Efficiency for CCA-Secure Cryptosystems Built Using Identity-Based Encryption (PDF), and the prover additionally has a decapsulation string for each of those.

If you weaken from proofs to arguments as described in the paper Zero Knowledge and Soundness are Symmetric (PDF), then you could let the encapsulation scheme(s) be only computationally binding or instead have the balances be signed in a suitable format, where the prover and verifier both know the signature verification key(s).