Patrick,

Well you uncovered something strange which maybe you can offer some advice on.  I was reading the prices from my Amibroker chart of MDY and although I had accidentally typed in 2006, instead of 2007, in my spreadsheet, the prices in my spreadsheet were what was shown on my Amibroker chart.

eg 3-5-2007 (not 2006)

and March 26, 2007 (not 2006);

I checked the prices on google and yahoo on these particular days and they are significantly different.  I originally downloaded pricing from yahoo and more recently switched to the Amiquote automatic update.  How can the pricing I downloaded be so off?  Now I wonder if any of my downloaded historical pricing is correct.  Any ideas?

Don

Patrick,

Thanks for the information.  I deleted the symbol from my Amibroker data base and then reloaded it using Amiquote. Same problem.  I deleted it again and used the free Yahoo downloader I have and had the same problem.  Yet, when I go to Yahoo and check the historical prices on Yahoo finance the Yahoo prices appear correct.  Strange.

Anyway, I re-did my spreadsheet with opening day pricing from BigCharts and checked the prices against the Yahoo historical pricing on-line.  There still seems to be a discrepancy in the profit generated.  Can you figure out why now?  ( I ignored amy dividends received).

MTR-TM Signal Date	Trade		Buy / Sell Date	Value MDY at Open	Profit / Loss	Profit / Loss	Long Total
5/16/2006	Down
6/30/2006								$10,000
8/18/2006	Up	1	Buy	8/21/2006	$136.7100
3/2/2007	Down	2	Sell	3/5/2007	$148.6000	8.7%	$870	$10,870
3/23/2007	Up	3	Buy	3/26/2007	$155.8100
7/27/2007	Down	4	Sell	7/30/2007	$155.9500	0.1%	$10	$10,879
9/19/2007	Up	5	Buy	9/20/2007	$161.2300
10/19/2007	Down	6	Sell	10/22/2007	$158.1200	-1.9%	-$210	$10,670
12/3/2007	Up	7	Buy	12/4/2007	$154.7500
1/4/2008	Down	8	Sell	1/7/2008	$149.0600	-3.7%	-$392	$10,277
1/28/2008	Up	9	Buy	1/29/2008	$144.1600
3/5/2008	Down	10	Sell	3/6/2008	$142.9600	-0.8%	-$86	$10,192
3/24/2008	Up	11	Buy	3/25/2008	$143.1000
6/11/2008	Down	12	Sell	6/12/2008	$155.7500	8.8%	$901	$11,093
7/21/2008	Up	13	Buy	7/22/2008	$145.4800
9/9/2008	Down	14	Sell	9/10/2008	$140.1600	-3.7%	-$406	$10,687
11/3/2008	Up	15	Buy	11/4/2008	$105.1400
11/11/2008	Down	16	Sell	11/12/2008	$91.8400	-12.6%	-$1,352	$9,335
12/3/2008	Up	17	Buy	12/4/2008	$88.1900
1/14/2009	Down	18	Sell	1/15/2009	$91.0500	3.2%	$303	$9,638
3/13/2009	Up	19	Buy	3/16/2009	$84.1200
6/18/2009	Down	20	Sell	6/19/2009	$105.6900	25.6%	$2,471	$12,109
7/1/2009	Up	21	Buy	7/2/2009	$104.4800
7/7/2009	Down	22	Sell	7/8/2009	$100.2200	-4.1%	-$494	$11,616
7/16/2009	Up	23	Buy	7/17/2009	$107.4300
10/26/2009	Down	24	Sell	10/27/2009	$126.3000	17.6%	$2,040	$13,656
11/9/2009	Up	25	Buy	11/10/2009	$126.3600
1/26/2010	Down	26	Sell	1/27/2010	$130.4600	3.2%	$443	$14,099
Actual Profit:	40.99%
MTR-TM Amibroker:	60.63%