No officer, director, or employee of any corporation or unincorporated association, no partner or employee of any partnership, and no individual, primarily engaged in the issue, flotation, underwriting, public sale, or distribution, at wholesale or retail, or through syndicate participation, of stocks, bonds, or other similar securities, shall serve [at] the same time as an officer, director, or employee of any member bank * * *.
12 C.F.R. §250.411
12 U.S.C. 248(i)