Grant Park Futures Fund Limited Partnership 424B3 Prospectus supplement

Filed Pursuant to Rule 424(b)(3)

File No. 333-153862

Grant Park Fund July 2010 Update

August 18, 2010

Supplement dated August 18, 2010 to Prospectus dated April 1, 2010

Class	July  ROR	YTD ROR	Net Asset Value	Net Asset Value per Unit
A	-1.7%	-7.4%	$59.8M	$1,320.10
B	-1.7%	-7.7%	$596.4M	$1,129.76
Legacy 1	-1.5%	-6.4%	$6.1M	$904.64
Legacy 2	-1.5%	-6.5%	$5.6M	$901.77
Global 1	-2.5%	-6.6%	$8.1M	$893.95
Global 2	-2.5%	-6.8%	$15.2M	$889.19
Global 3	-2.7%	-7.8%	$100.7M	$866.61

ALL PERFORMANCE REPORTED IS NET OF FEES AND EXPENSES

Sector Commentary

Agriculturals/Softs:  Grains prices generally rose.  Unusually warm temperatures in major U.S. farming regions dampened previous predictions of record-breaking harvests for 2010.  Severe droughts in Eastern Europe increased international demand for U.S. crops and further contributed to the rally in the grains.  In the softs markets, sugar prices rose over 8% as forecasts for future global demand and export delays from Brazil supported prices.

Currencies:  Investors sold the U.S. dollar because of weak economic data including poor consumer sentiment and lower-GDP- growth data.  The results from recent stress tests on the EU financial system resulted in gains in the euro.  Comments from the Bank of Japan citing expanding growth forecasts strengthened the yen over many major counterparts.

Energy:  An unexpected drop in U.S. fuel inventories led to gains in the crude oil markets.  In the natural gas markets, continued warm temperatures and forecasts for elevated hurricane activity for 2010 drove prices nearly 7% higher over June’s closing prices.

Equities:   North American equity markets generally rose last month as key U.S. firms reported stronger-than-expected second-quarter corporate earnings.  European equity markets made strong gains in July, propelled by the positive results from recent stress tests on the EU financial sector.  Asian markets also moved higher, predominantly driven by strength in the natural resources sector.

Fixed Income:  A drop in U.S. investor sentiment resulted in stronger demand for U.S. fixed-income products, thereby moving prices higher.  Also adding to the rally in the debt markets was short-term weakness in the equity markets that occurred early in the month following the release of pessimistic reports concerning U.S. growth forecasts.

Metals:  Precious metals markets predominantly fell in July as renewed recovery hopes for Europe decreased the need for euro-hedging precious metals positions.  Conversely, an improved outlook for the Eurozone bode well for the base metals markets, as investors speculated that an improving global economy would boost industrial demand.  Also supporting the base metals markets was news that U.S. existing home sales decreased by less than originally expected in June.

Sincerely,

David Kavanagh

President

Enclosures

Daily fund performance and weekly commentaries are available on our website at www.grantparkfunds.com.

PAST PERFORMANCE IS NOT INDICATIVE OF FUTURE RESULTS

FUTURES TRADING INVOLVES A HIGH DEGREE OF RISK AND IS NOT SUITABLE FOR ALL INVESTORS

THIS DOES NOT CONSTITUTE AN OFFER OF ANY SECURITY FOR SALE NOR SHALL THERE BE ANY SALE OF SECURITIES IN ANY JURISDICTION IN WHICH AN OFFER, SOLICITATION OR SALE WOULD BE UNLAWFUL PRIOR TO REGISTRATION OR QUALIFICATION UNDER THE SECURITIES LAWS OF ANY SUCH JURISDICTION OFFERING BY PROSPECTUS ONLY.

Account Statement

(Prepared from books without audit)

For the month ended July 31, 2010

STATEMENT OF INCOME
Trading Income (Loss)	Month to Date Total		Year to Date Total
Realized Trading Income (Loss)	$	-23,245,068	$	-34,913,426
Change In Unrealized Income (Loss)		13,194,131		7,200,938
Brokerage Commission		-460,112		-3,711,531
Exchange, Clearing Fee and NFA Charges		-53,066		-315,076
Other Trading Costs		-567,451		-3,204,132
Change in Accrued Commission		71,841		101,832
Net Trading Income (Loss)		-11,059,725		-34,841,395
Other Income	Month to Date Total		Year to Date Total
Interest, U.S. Obligations	$	154,470	$	1,245,461
Interest, Other		245,221		1,620,741
U.S. Government Securities Gain (Loss)		0		0
Total Income (Loss)		-10,660,034		-31,975,193
Expenses	Month to Date Total		Year to Date Total
Management Fee	$	0	$	0
Incentive Fee		3,378		1,384,311
Operating Expenses		168,131		1,188,150
Organization and Offering Expenses		191,666		1,349,723
Brokerage Expenses		4,094,103		29,237,364
Total Expenses		4,457,278		33,159,548
Net Income (Loss)	$	-15,117,312	$	-65,134,741
Statement of Changes in Net Asset Value	Month to Date Total		Year to Date Total
Beginning Balance	$	808,707,540	$	831,270,498
Additions		8,415,790		85,511,900
Net Income (Loss)		-15,117,312		-65,134,741
Redemptions		-10,059,510		-59,701,149
Balance at JULY 31, 2010	$	791,946,508	$	791,946,508

PERFORMANCE SUMMARY BY CLASS

Class	Net Asset Value per Unit	Units	Net Asset Value	ROR – Month to Date       ROR – Year to Date
A	$1,320.099	45,313.85376	$59,818,789	-1.66%	-7.37%
B	$1,129.760	527,908.66854	$596,410,080	-1.71%	-7.73%
Legacy 1	$904.643	6,785.81589	$6,138,739	-1.50%	-6.36%
Legacy 2	$901.767	6,180.78993	$5,573,634	-1.52%	-6.51%
Global 1	$893.948	9,067.83603	$8,106,173	-2.51%	-6.57%
Global 2	$889.186	17,146.16261	$15,246,131	-2.53%	-6.75%
Global 3	$866.608	116,145.92222	$100,652,962	-2.67%	-7.77%

To the best of my knowledge and belief the information contained herein is accurate and complete.

__________________________________________________________

David Kavanagh, President

For Dearborn Capital Management, LLC

General Partner of Grant Park Futures Fund, Limited Partnership