For purposes of paragraph (1) of this subsection, and of section
77ppp
(a) of this title, the term “series of securities” or “series” means a series, class or group of securities issuable under an indenture pursuant to whose terms holders of one such series may vote to direct the indenture trustee, or otherwise take action pursuant to a vote of such holders, separately from holders of another such series: Provided, That “series of securities” or “series” shall not include any series of securities issuable under an indenture if all such series rank equally and are wholly unsecured.
The specification of percentages in paragraphs (5) to (9), inclusive, of this subsection shall not be construed as indicating that the ownership of such percentages of the securities of a person is or is not necessary or sufficient to constitute direct or indirect control for the purposes of paragraph (3) or (7) of this subsection.
(C)
the indenture trustee shall not be deemed the owner or holder of
(i)
any security which it holds as collateral security (as trustee or otherwise) for any obligation which is not in default as above defined, or
(ii)
any security which it holds as collateral security under the indenture to be qualified, irrespective of any default thereunder, or
(iii)
any security which it holds as agent for collection, or as custodian, escrow agent or depositary, or in any similar representative capacity.
For the purposes of this subsection, the term “underwriter” when used with reference to an obligor upon the indenture securities means every person who, within one year prior to the time as of which the determination is made, was an underwriter of any security of such obligor outstanding at the time of the determination.
Except in the case of a default in the payment of the principal of or interest on any indenture security, or in the payment of any sinking or purchase fund installment, the indenture trustee shall not be required to resign as provided by this subsection if such trustee shall have sustained the burden of proving, on application to the Commission and after opportunity for hearing thereon, that—