C.C.A. 201308028 (Nov. 14, 2012)

(irrespective of whether LLC treated as partnership or disregarded entity, guarantor of LLC debt can be at risk for purposes of I.R.C. Sec. 465(loss deductibility) even if guarantor does not waive rights of subrogation and right to be reimbursed from LLC; but, to extent debt is co-guaranteed, guarantor not at risk; IRS views guaranteeing debt as being "at risk" and personally liable for the debt; IRS following approach of 2d, 8th and 11th Circuits - taxpayer ultimately liable as payor of last resort and taxpayer not protected against loss; where loan co-guaranteed, taxpayer protected against loss and not at risk).