Quick answerIndiana sells tax lien certificates for unpaid property taxes. Lien buyers can earn Premium (overbid) auction; return is penalty-based, not a bid interest rate. On redemption the owner pays 110% of the minimum bid if redeemed within 6 months, or 115% of the minimum bid if redeemed after 6 months and within 1 year (i.e., a 10% or 15% penalty on the minimum-bid portion), plus 5% per annum on the portion of the purchase price above the minimum bid and 5% per annum on subsequent taxes paid by the buyer, for sales after June 30, 2014 (IC 6-1.1-25-2). The overbid principal itself is returned on redemption; it is not forfeited.. Redemption: 1 year from the date of sale (IC 6-1.1-25-4); only 120 days for certificates acquired by the county commissioners (county-held certificates) and for certain purchasing agencies. Sales: Annual county tax sales in the fall, mostly September-October; unsold certificates later go to a commissioners' (county executive) certificate sale, typically in the following winter/spring. Governing law: Indiana Code 6-1.1-24 (tax sale) and 6-1.1-25 (redemption and tax deeds), esp. IC 6-1.1-25-2 and IC 6-1.1-24-6.1 (commissioners' sale).