IRS proposes rules that would provide a limited exception to anti-cutback rules, allowing a plan sponsor that is a debtor in a bankruptcy proceeding to amend its single-employer pension plan to eliminate a lump-sum distribution option in some cases. The proposed regulations (REG-113738-12) would allow an amendment to eliminate a lump-sum distribution option—or other optional form of benefit providing for accelerated payments—if the four conditions are met.