Since the start of computer automation for the auction processes more than 20 years ago, the time it takes the Treasury Department to aggregate the auction bids and release the results has shorten drastically.
I checked the release time today for data relating to the 2-year auction today (April 24, 2012). For each auction, 2 pieces of information are released. For Treasury notes and bonds, the noncompetitive bidding closes at 12:00 p.m. EST. The results for the noncompetitive bidding is supposed to be released about 15 minutes before the close of competitive bidding (12:45 p.m. EST). The competitive bidder closes at 1 p.m. EST. Then the result to the auction is released soon afterwards. The figure below links to the result announcements and updates throughout the day (webpage here).
The preliminary noncompetitive results were released on about 12:46 p.m. EST (a minute later than the approximate official release time.) The auction results were released on 1:03 p.m. EST (i.e., 3 minutes after the bidder closes). The snapshot below from my iTouch shows the time of release. (I was refreshing the webpage minutely while sitting in an econometrics class; I am on Pacific Standard time.)
What this mean is that the after auction closes, the computer system aggregates the bids, calculate the equilibrium yield, and issue the results in minutes. In fact, if you check the PDF document property (figure below), the PDF creation date is 10:01:47 a.m. Assuming my PDF reader converted the creation time to PST, it means all the results were already complicated a minute 47 seconds after the auction closes.
