(a) Annual insolvency determination. A plan that has no benefits subject to reduction and has assets insufficient to discharge when due all of the plan's obligations with respect to nonforfeitable benefits must make periodic determinations of plan solvency in accordance with this paragraph (a). No later than six months before the beginning of the applicable plan year described in this paragraph (a), or as soon as practicable after the plan sponsor determines the applicable plan year, and no later than six months before each plan year thereafter, the plan sponsor must determine in writing whether the plan is expected to be insolvent for such plan year. The applicable plan year is -

(b) Other determination of insolvency. Whether or not a prior determination of plan insolvency has been made under paragraph (a) of this section (or under section 4245 of ERISA), a plan sponsor that has reason to believe, taking into account the plan's recent and anticipated financial experience, that the plan is insolvent in the current plan year or is expected to be insolvent in the next plan year must determine in writing whether the plan is or is expected to be insolvent for that plan year.

(c) Benefit suspensions. If the plan sponsor determines that the plan is, or is expected to be, insolvent for a plan year, it must suspend benefits in accordance with § 4281.41.

(d) Insolvency notices. If the plan sponsor determines that the plan is insolvent in the current plan year or is expected to be insolvent in the next plan year it must provide notices of insolvency and notices of insolvency benefit level to PBGC and to participants and beneficiaries in accordance with subpart D of part 4281 of this chapter.