(a) In general. This section sets forth certain rules that apply to statutory hybrid plans under section 411(a)(13). Paragraph (b) of this section describes special rules for certain statutory hybrid plans that determine benefits under a lump sum-based benefit formula. Paragraph (c) of this section describes the vesting requirement for statutory hybrid plans. Paragraphs (d) and (e) of this section contain definitions and effective/applicability dates, respectively.