37 C.F.R. § 11.115 – Safekeeping property.

(a) A practitioner shall hold property of clients or third persons that is in a practitioner's possession in connection with a representation separate from the practitioner's own property. Funds shall be kept in a separate account maintained in the state where the practitioner's office is situated, or elsewhere with the consent of the client or third person. Where the practitioner's office is situated in a foreign country, funds shall be kept in a separate account maintained in that foreign country or elsewhere with the consent of the client or third person. Other property shall be identified as such and appropriately safeguarded. Complete records of such account funds and other property shall be kept by the practitioner and shall be preserved for a period of five years after termination of the representation.
(b) A practitioner may deposit the practitioner's own funds in a client trust account for the sole purpose of paying bank service charges on that account, but only in an amount necessary for that purpose.
(c) A practitioner shall deposit into a client trust account legal fees and expenses that have been paid in advance, to be withdrawn by the practitioner only as fees are earned or expenses incurred.
(d) Upon receiving funds or other property in which a client or third person has an interest, a practitioner shall promptly notify the client or third person. Except as stated in this section or otherwise permitted by law or by agreement with the client, a practitioner shall promptly deliver to the client or third person any funds or other property that the client or third person is entitled to receive and, upon request by the client or third person, shall promptly render a full accounting regarding such property.
(e) When in the course of representation a practitioner is in possession of property in which two or more persons (one of whom may be the practitioner) claim interests, the property shall be kept separate by the practitioner until the dispute is resolved. The practitioner shall promptly distribute all portions of the property as to which the interests are not in dispute.
(f) All separate accounts for clients or third persons kept by a practitioner must also comply with the following provisions:
1. (1) Required records. The records to be kept include:
  1. (i) Receipt and disbursement journals containing a record of deposits to and withdrawals from client trust accounts, specifically identifying the date, source, and description of each item deposited, as well as the date, payee and purpose of each disbursement;
  2. (ii) Ledger records for all client trust accounts showing, for each separate trust client or beneficiary, the source of all funds deposited, the names of all persons for whom the funds are or were held, the amount of such funds, the descriptions and amounts of charges or withdrawals, and the names of all persons or entities to whom such funds were disbursed;
  3. (iii) Copies of retainer and compensation agreements with clients;
  4. (iv) Copies of accountings to clients or third persons showing the disbursement of funds to them or on their behalf;
  5. (v) Copies of bills for legal fees and expenses rendered to clients;
  6. (vi) Copies of records showing disbursements on behalf of clients;
  7. (vii) The physical or electronic equivalents of all checkbook registers, bank statements, records of deposit, pre-numbered canceled checks, and substitute checks provided by a financial institution;
  8. (viii) Records of all electronic transfers from client trust accounts, including the name of the person authorizing transfer, the date of transfer, the name of the recipient and confirmation from the financial institution of the trust account number from which money was withdrawn and the date and the time the transfer was completed;
  9. (ix) Copies of monthly trial balances and quarterly reconciliations of the client trust accounts maintained by the practitioner; and
  10. (x) Copies of those portions of client files that are reasonably related to client trust account transactions.
2. (2) Client trust account safeguards. With respect to client trust accounts required by paragraphs (a) through (e) of this section:
  1. (i) Only a practitioner or a person under the direct supervision of the practitioner shall be an authorized signatory or authorize transfers from a client trust account;
  2. (ii) Receipts shall be deposited intact and records of deposit should be sufficiently detailed to identify each item; and
  3. (iii) Withdrawals shall be made only by check payable to a named payee and not to cash, or by authorized electronic transfer.
3. (3) Availability of records. Records required by paragraph (f)(1) of this section may be maintained by electronic, photographic, or other media provided that they otherwise comply with paragraphs (f)(1) and (f)(2) of this section and that printed copies can be produced. These records shall be readily accessible to the practitioner.
4. (4) Lawyers. The records kept by a lawyer are deemed to be in compliance with this section if the types of records that are maintained meet the recordkeeping requirements of a state in which the lawyer is licensed and in good standing, the recordkeeping requirements of the state where the lawyer's principal place of business is located, or the recordkeeping requirements of this section.
5. (5) Patent agents and persons granted limited recognition who are employed in the United States by a law firm. The records kept by a law firm employing one or more registered patent agents or persons granted limited recognition under § 11.9 are deemed to be in compliance with this section if the types of records that are maintained meet the recordkeeping requirements of the state where at least one practitioner of the law firm is licensed and in good standing, the recordkeeping requirements of the state where the law firm's principal place of business is located, or the recordkeeping requirements of this section.