I'm interested in this massive sell too. I pulled some historical data on mtgoxUSD from the last two days from bitcoincharts.com, pulled out all the transactions over 500 BTC, and sorted them by date. Here are the results:
'2011-11-14 01:50:12 2.900000 1000.000000'
'2011-11-14 01:50:21 2.840000 1000.000000'
'2011-11-14 01:50:22 2.831100 985.126022'
'2011-11-14 01:50:22 2.830000 1000.000000'
'2011-11-14 01:50:23 2.820000 1000.000000'
'2011-11-14 01:50:24 2.820000 590.000000'
'2011-11-14 01:50:27 2.800010 567.623000'
'2011-11-14 01:50:29 2.800000 1000.000000'
'2011-11-14 01:50:36 2.750110 727.243600'
'2011-11-14 01:50:37 2.750000 1400.674735'
'2011-11-14 01:50:47 2.700000 606.000000'
'2011-11-14 01:50:56 2.622850 1399.994933'
'2011-11-14 01:52:30 2.502000 639.435000'
'2011-11-14 01:52:31 2.500010 583.447762'
'2011-11-14 01:52:33 2.500000 600.000000'
'2011-11-14 01:52:34 2.500000 1200.000000'
'2011-11-14 02:05:38 2.500000 746.660808'
'2011-11-14 02:39:38 2.500000 2000.000000'
'2011-11-14 02:41:55 2.500000 531.199040'
'2011-11-14 02:42:08 2.500000 650.000000'
'2011-11-14 02:55:28 2.510000 547.257017'
'2011-11-14 02:59:33 2.520000 1000.000000'
'2011-11-14 03:03:27 2.554000 933.400898'
'2011-11-14 03:04:54 2.500010 697.915126'
'2011-11-14 03:05:39 2.500010 941.542810'
'2011-11-14 03:07:19 2.500010 921.153747'
'2011-11-14 03:07:44 2.500010 545.196484'
'2011-11-14 03:08:29 2.500010 1000.000000'
'2011-11-14 03:08:29 2.500010 1000.000000'
'2011-11-14 03:08:29 2.500010 1000.000000'
'2011-11-14 03:08:29 2.500010 1000.000000'
'2011-11-14 03:08:29 2.500010 1000.000000'
'2011-11-14 03:10:03 2.500000 3000.000000'
'2011-11-14 03:14:42 2.500010 641.667193'
'2011-11-14 03:14:42 2.500010 1000.000000'
'2011-11-14 03:14:42 2.500010 1000.000000'
'2011-11-14 03:14:42 2.500010 1000.000000'
'2011-11-14 03:14:42 2.500010 1000.000000'
'2011-11-14 03:14:42 2.500010 1000.000000'
'2011-11-14 03:17:44 2.500010 1000.000000'
'2011-11-14 03:19:13 2.500010 684.136107'
'2011-11-14 03:29:12 2.550010 1000.000000'
'2011-11-14 03:29:12 2.550010 1000.000000'
'2011-11-14 03:29:12 2.550010 1000.000000'
'2011-11-14 03:29:12 2.550010 1000.000000'
'2011-11-14 03:38:21 2.600000 4662.885952'
'2011-11-14 03:38:30 2.600000 5000.000000'
'2011-11-14 03:38:42 2.600000 5000.000000'
'2011-11-14 03:46:01 2.600000 9994.348607'
'2011-11-14 03:46:13 2.560000 6728.658203'
'2011-11-14 03:46:20 2.500000 2466.881068'
'2011-11-14 03:46:48 2.500000 2533.118932'
'2011-11-14 03:47:40 2.500000 5000.000000'
'2011-11-14 03:51:40 2.700000 1000.000000'
'2011-11-14 03:53:45 2.600000 854.070454'
'2011-11-14 03:53:45 2.600000 3253.273450'
'2011-11-14 04:17:31 2.500010 1000.000000'
'2011-11-14 04:18:22 2.500000 971.167778'
'2011-11-14 04:18:24 2.500010 1000.000000'
'2011-11-14 04:19:07 2.500010 885.198095'
'2011-11-14 04:19:12 2.500010 1018.300591'
'2011-11-14 04:21:50 2.500000 1000.000000'
'2011-11-14 04:24:26 2.500010 9701.376317'
'2011-11-14 04:30:58 2.510000 1593.625500'
'2011-11-14 04:32:48 2.500010 20000.000000'
'2011-11-14 04:33:50 2.500000 2000.000000'
'2011-11-14 04:35:30 2.450000 897.280294'
'2011-11-14 04:36:33 2.500000 736.100000'
'2011-11-14 04:53:35 2.400010 6742.163703'
'2011-11-14 05:05:59 2.480000 754.548202'
'2011-11-14 05:14:03 2.411190 999.615136'
'2011-11-14 05:14:06 2.400000 5000.000000'
So in the 44 seconds from 01:50:12 to 01:50:56 we had a trading volume of 11,275 BTC. Such a sudden spike looks a lot like a single person selling. Of course it *could* be a single person triggering trading bots as well.
Then about 1 hour and 18 minutes pass, with high volume trading, but much less sudden and a bit more evenly distributed. 12,533 BTC are sold in these circa 80 minutes.
Then another huge sell, 5000 BTC all at once at 03:08:29 happens. 5000 BTC in a single second!
This exact same thing happens about 6 minutes later at 03:14:42 - 5641.66 BTC in a single second. Dude waits 15 minutes more - I'm assuming it's one guy - and dumps 4000 BTC at 03:29:12.
It's the initial sells at 01:50:12 to 01:52:33 that effectively drops the price from 2.90 to 2.50 in a little over 2 minutes.
Only counting the trades of at least 500 BTC in the period from
2011-11-14 01:50:12 to
2011-11-14 05:14:06 amounts to 144,000 BTC being traded in this 3½ hour period.
I wonder who's doing this. It must be an early adopter right? I mean, who else has this much BTC on hand?