I'm desparately searching the Iowa code for info on what state-chartered banks can and cannot do with buying and seling of particpations on commercial loans. Can anyone get me to the code section? Please.....

There isn't much in the Code. Code section 524.907 has literally ONE sentence that essentially says a bank may use participations:

524.907 Participations.
A state bank may purchase and may sell, subject to the provisions of sections 524.901, 524.904, and 524.905, and to such regulations as the superintendent may prescribe, participations in one or more evidences of indebtedness and agreements for the payment of money, and pools of bonds, securities, evidences of indebtedness and agreements for the payment of money.