The IRS has issued proposed regulations that provide guidance on the recovery of overpayments of arbitrage rebate on tax-exempt bonds and other tax-advantaged bonds, including the deadline for filing a claim for an arbitrage rebate overpayment. (REG-148812-11)
http://www.ofr.gov/(S(cpohw1vx1p4rtqqy5mcjrmz4))/OFRUpload/OFRData/2013-21879_PI.pdf