Under section 103(c)(1) and this section, an industrial development bond issued after April 30, 1968, shall be treated as an obligation not described in section 103(a)(1) and section 1.103-1. Accordingly, interest paid on such a bond is includable in gross income unless the bond was issued by a State, or local governmental unit to finance certain exempt facilities (see section 103(c)(4) and section 1.103-8), to finance an industrial park (see section 103(c)(5) and section 1.103-9), or as part of an exempt small issue (see section 103(c)(6) and section 1.103-10). For applicable rules when an industrial development bond is held by a substantial user (or a person related to a substantial user) of such an exempt facility, or an industrial park, or a facility financed with the proceeds of such an exempt small issue, see section 103(c)(7) and section 1.103-11. See also section 1.103-12 for the transitional provisions concerning the interest paid on certain industrial development bonds issued before January 1, 1969, and certain other industrial development bonds. Even if section 103(c) does not prevent a bond from being treated as an obligation described in section 103(a)(1) and section 1.103-1, such bond shall nevertheless be treated as an obligation which is not described in section 103(a)(1) and section 1.103-1 if under section 103(d) it is an arbitrage bond. For purposes of section 103(c), the term “issue” includes a single obligation such as a single note issued in connection with a bank loan as well as a series of notes or bonds.