Bidding Rules

Information on the Public Auction of Delinquent Real Property Tax Liens

Bidding Rules

Summary of Important Dates


City and County of Denver Information on the Public Auction of Delinquent Real Property Tax Liens


The Tax Lien Public Auction is usually held around the first part of November; however, 2020 auction is scheduled in October earlier than usual. Buyers pay the total advertised price consisting of tax, interest to the date of public auction and an advertising fee. They also pay a $4.00 certificate fee and an $8.00 auction fee plus any premium bid. The person paying the highest amount is issued a Certificate of Purchase. This is a negotiable document representing a lien on the property. It is valid for 15 years. The buyer does not recover the premium paid over the starting amount. The certificate earns interest at the rate stated on the certificate with portions of calendar months considered as whole months.

A buyer list showing certificate numbers, parcel numbers and total paid will be provided to the taxpayer. Buyers are responsible for keeping adequate records. The Treasury Division is responsible for the public auction of the tax lien, immediate notification to buyers of redemptions and payment upon surrender of the redeemed certificate. (We will hold your certificate if you wish and provide copies to you.)

The redemption amount paid is the certificate amount (tax, interest, advertising, and fees), plus redemption interest. The annual redemption interest rate for each year’s public auction is established by adding 9% to the September 1st Federal Reserve discount rate. One twelfth of this rate accrues for each month or portion thereof. The September 1, 2020 discount rate was 0.25%. The redemption rate for certificates sold in October of 2020 will be 9% or 0.75% per month. Upon redemption, we notify the buyer to return their certificate for payment of the certificate face value plus accrued interest. If we are holding your certificate, a check will be mailed immediately.

Buyers may after July 1st pay the subsequent year’s unpaid taxes for endorsement onto their certificates. These payments earn the same rate of interest as does the original public auction.

If the property has not been redeemed after three years from the date of public auction, the buyer can apply for and receive a Treasurer’s Deed to the property. Buyers return their certificates to us and deposit expense money. After a title search, advertising, and notification of all interested parties, a Treasurer’s Tax Deed is issued if there has been no redemption.

Erroneous sales are paid interest at the rate of 2% above the discount rate rounded to the nearest full percent but no lower than 8%. The lower redemption interest rate is applicable to discoveries made after May 23, 1988 and can be applied to the entire certificate regardless of when the certificate was purchased.

If you wish to participate in our public auction, visit our auction website at for the rules and any details. The list of parcels for sale will be available at the auction website about two weeks before the auction starts.

The subject of Tax Lien Public Auctions, Deeds, Redemptions, etc., which are administered by County Treasurers, is covered by Colorado Revised Statutes, Title 39, Articles 11, and 12. Any questions should be referred to the Taxpayer Service Unit at (720) 913-9500.



City and County of Denver Bidding Rules for the Treasurer's Annual Public Auction of Real Estate Tax Liens for Tax Year 2019

Bidding rules


Each bidder must register on the Auction Website before they will be allowed to participate in the tax lien sale.  After registering, each bidder will receive a bidding number from the Auction Website that will enable the bidder to place bids.  All bidders must make a deposit on the Auction Website before their bids will be accepted.  Registration and deposits may be made starting Monday, September 28th, 2020, and must be completed no later than Wednesday, October 7th, 2020, at 2:00 PM MDT.  No registration or deposits will be allowed after this time.  Each bidder shall make a deposit equal to Ten percent (10%) of the total dollar amount of tax liens the bidder anticipates winning. All deposits shall be made by electronic funds transfer. Final determination regarding the acceptability of any deposit will be at the discretion of the Treasurer.  If a bidder’s deposit drops below Ten percent (10%) of the total dollar amount of all tax liens won, plus the amount of active bids, while there are still active bids, the active bids will not be accepted.  Buyers are responsible to ensure the information on their registration is correct since certificates of purchase, redemption checks and refund checks are prepared from this information.

In accordance with §39-11-115 (2) (c) and (d), C.R.S., minimum bids and bid increase increments are as follows:

Minimum bids: The minimum starting bid for each tax lien is equal to the amount of the unpaid taxes, interest, penalties, and fees (the tax lien face value).

Bid increments: Bid increments shall be One dollar ($1.00). Tax liens are awarded to the highest bidder, or in the event of a tie, the winner will be selected at random by the Auction Website, and the winning bid amount will equal the amount of the tie bid.

Tax liens will be grouped into batches and sold in one hour increments starting on Wednesday, October 14th, 2020, at 8:00 AM MDT and concluding on Wednesday, October 14th, 2020, at 5:00 PM MDT. Tax liens in each batch will be identified with a closing time.

Bids may be made starting Monday, October 12th, 2020, at 8:00 AM MDT. Bids will be accepted for each tax lien until the batch containing it closes. The Auction Website stores the bids for each tax lien until the batch containing it closes. Prior to the closing of the batch, bidders may change or withdraw their bids. Once a batch closes, the bids become final and may not be changed or withdrawn.

Payment for the total amount of the bidder's winning bids shall be automatically initiated via an Automated Clearing House (ACH) debit no later than Thursday, October 15th, 2020 at 2:00 PM MDT. The account debited will be the last successful deposit account. If a winning bidder fails to pay the amount by this time, the Treasurer may, in the Treasurer’s sole discretion, award the tax liens to another bidder or may offer the tax lien for sale. The Treasurer may prohibit a person, who fails to pay the amount due from bidding, from participating in any tax lien sales for up to five years in accordance with § 39-11-116, C.R.S.

The certificate of purchase issued on a successful bid will show the legal description, purchase amount, and buyer’s name (as entered in registration), interest rate, and date of sale. Buyers will be notified when their certificates are ready to be picked up. The City and County of Denver will keep them if the buyer wishes and provide copies.

Redemption interest is 9% per annum. If parcels are redeemed prior to delivery of certificates, redemption checks will be mailed to buyers and notations made on buyers’ lists of purchases.

Employees and officials of the City and County of Denver, and members of their families are not allowed to purchase at the Public Auction.



  • Those investing in tax liens do so at their own risk and are advised to exercise due diligence in carefully analyzing which tax liens to bid on. There are no guarantees expressed or implied regarding whether a tax lien will prove to be a profitable investment.

  • The property information accessible on the bid pages was obtained from the Assessor’s office prior to the start of the current auction and is for reference only (please note that this property information, provided by the Assessor’s office, represents the most current assessment year, not the tax year associated with this tax lien sale, as taxes are paid one year in arrears). It is the buyer’s responsibility to research auction items thoroughly prior to placing bids.

  • Do not attempt to make any name changes to your existing account. To make a name change, you must contact the Treasury Division at (720) 913-9500.


Summary of Important Dates

  Bidder Accounts  
  Allow foreign bidder registrations     Yes
  Single simultaneous bidder rule     No
  Auction Information  
  Bidding style     Proxy Bid Auction
  0 value bids use proxy system     No
  Allow sub-accounts     No
  Automatic certificate rollup / rollup fee   --- ---
  Auction Dates and Times  
  Registration begins (site opens)**     09/28/2020 at 8:00 AM MDT  
  Deposits, Registration fees and Budgets begin     09/28/2020 at 8:00 AM MDT  
  Bidding begins     10/12/2020 at 8:00 AM MDT  
  Deposits, Registration fees and Budgets end       10/07/2020 at 2:00 PM MDT   
  Participation Requirements  

  Participation Requirements Due Date     10/07/2020 at 2:00 PM MDT   
  Registrations end     10/07/2020 at 2:00 PM MDT   
  First batch closes     10/14/2020 at 8:00 AM MDT   
  Batch closing interval     60 Minutes
  Last batch closes     10/14/2020 at 5:00 PM MDT  
  Auxiliary batch opens     N/A  
  Auxiliary batch closes     N/A  
  Payment due date     10/15/2020 at 2:00 PM MDT   
  Budget, Deposit and Payment Information    
  Deposit or Budget required (% of estimated winnings)     10%
  Minimum deposit amount     $0.00
  Registration Fee     $0.00
  Registration Fee Refundable      Yes
  Registration Fee Applied to Winnings      Yes
  Deposit / Payment types acceptable:   Deposits Payments
      Budget    No ---
      ACH    Yes No
      ACH auto-debit final payment    --- Yes
      Wire transfers   No No
      Counter payments   No No
  Redemptions available via ACH?   Yes
  Public Access  
  Public computers available   Wellington E Webb Municipal Office Building, City and County of Denver, 201 West Colfax Ave, Denver, Colorado, located in the Assessors Office, 4th floor reception area
  ** Subject to change. The site will open when approved by the County.  


For an explanation of any of the terms above, please visit the FAQs.


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