10 Pa. Code § 9.4
An IRA account may be commingled or pooled only if permitted under § 9.2 or § 9.3 (relating to institutions without fiduciary and other representative powers; and institutions with fiduciary and other representative powers), and only to the extent the commingling or pooling is permitted by the instruments creating the account, laws applicable to the account, and the applicable rules and regulations of the Internal Revenue Service and the department or agency of the United States which insures the account. Any such commingling by an institution shall also be subject to Chapter 15 (relating to trusts) to the extent that the requirements of Chapter 15 do not conflict with the requirements of the applicable Federal laws and the applicable rules and regulations of the Internal Revenue Service and the department or agency of the United States which insures the IRA accounts of the institution. An IRA account may be commingled by an institution only in a common trust or investment fund administered by the trust department of the institution which qualifies for exemption from tax under Internal Revenue Rulings and the Internal Revenue Code and which consists of pension, retirement and profit-sharing funds. Under no circumstances may an IRA account be pooled by an institution except in a time deposit administered by the institution which consists entirely of the funds from IRA accounts administered by the institution; nor may an IRA account be pooled by an institution which has both a commercial and a trust department except with other IRA accounts administered by the same department which administers the IRA account.
10 Pa. Code § 9.4
This section cited in 10 Pa. Code § 9.2 (relating to institutions without fiduciary and other representative powers); and 10 Pa. Code § 9.3 (relating to institutions with fiduciary and other representative powers).