Unassociated Document

Prospectus Supplement	Filed Pursuant to Rule 424(b)(7)
(To Prospectus dated October 26, 2009)	Registration No. 333-162551

Duff & Phelps Corporation

Class A Common Stock

________________

This prospectus supplement supplements and amends the prospectus dated October 26, 2009 relating, in part, to the resale from time to time of up to 19,618,979 shares of our Class A common stock by the selling stockholders described therein and in this prospectus supplement. The selling stockholders are offering all of the shares of our Class A common stock offered by this prospectus supplement. We will not receive any proceeds from the sale by the selling stockholders of shares of Class A common stock.

This prospectus supplement should be read in conjunction with and accompanied by the prospectus and is qualified by reference to the prospectus, except to the extent that the information in this prospectus supplement supersedes the information contained in the prospectus.

Our Class A common stock is listed on the New York Stock Exchange under the trading symbol “DUF.” The last reported sale price of our Class A common stock on November 11, 2010 was $14.96 per share.

Investing in our securities involves a high degree of risk. See “Risk Factors” on page 3 before you make your investment decision.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus or the accompanying prospectus supplement is truthful or complete. Any representation to the contrary is a criminal offense.

Prospectus Supplement dated November 12, 2010.

SELLING STOCKHOLDERS

The shares of Class A common stock offered by this prospectus supplement may be offered from time to time by the selling stockholders named below. Information concerning other selling stockholders will be set forth in other prospectus supplements from time to time, if required.

Beneficial ownership is determined in accordance with the rules of the SEC. These rules generally attribute beneficial ownership of securities to persons who possess sole or shared voting power or investment power with respect to such securities. Except as otherwise indicated, the persons listed below have sole voting and investment power with respect to the shares of Class A common stock beneficially owned by them, subject to applicable community property laws.

Except as otherwise indicated, the address for each selling stockholder is c/o Duff & Phelps Corporation, 55 East 52nd Street, 31st Floor, New York, New York 10055.

S-2

	Shares
	Offered		Class A Common Stock
	Hereby		on a Fully-Exchanged Basis(1)
Selling Stockholders	Number		Number			Percent(2)
Abello, Kim		3,068		-			-
Aders, Christian		6,968		11,362			*
Althoff, David		6,707		14,441			*
Arcy, Jerome		22,610		25,533			*
Athanason, Michael		21,159		-			-
Baldwin Jr., David		1,933		11,508			*
Bannon, Gary L.		26,838		17,741			*
Barnes, Paul F.		45,542		106,599			*
Bartell, Robert		7,802		82,774			*
Bayston, Daniel		25,620		3,253			*
Belinsky Family Trust		114,948		114,948			*
Benn, Joshua		16,868		53,645			*
Bluth, Elyse		19,453		23,475			*
Bollmann, Frank		1,933		6,088			*
Burt, Steve		32,191		89,383			*
Butcher, Scot		1,044		-			-
Cannaday, Sean		1,742		4,128			*
Cefali, David, 2007 Education Trust		8,522		-			-
Cefali, Sheryl		1,546		11,637			*
Cefali, Sheryl, 2007 Education Trust		8,522		-			-
Chrysostomou, Andreas		16,317		42,770			*
Clemens, Jack		1,933		27,815			*
Cody, Alan M.		47,624		3,750			*
Creagh, Gerard		65,803		252,820	(3)		*
Creagh, Gerard, Qualfied Annuity Trust		34,792		69,584			*
Cullen, Brian		13,610		21,927			*
Dolan, Michael		16,317		66,242			*
Dunne, Jeffrey D.		34,352		4,398			*
Fagan, Kevin		11,214		428			*
Franceschi, Greg S.		45,542		81,029			*
Gavin, James		10,840		10,404			*
Gilcreast, Aaron A.		471		-			-
Glace, Matthew		348		13,511			*
Golden, Timothy		9,912		12,148			*
Gordon, Jeffrey		23,357		10,815			*

S-3

	Shares
	Offered		Class A Common Stock
	Hereby		on a Fully-Exchanged Basis(1)
Selling Stockholders	Number		Number		Percent(2)
Grabowski Harte, Sarah		290		-		-
Grabowski Jr., Roger		290		-		-
Grabowski, Julia		290		-		-
Grabowski, Paul		290		-		-
Grabowski, The Roger, Trust		37,416		27,102		*
Grant, Dwight		5,662		36,373		*
Herman, Robert		348		43,964		*
Herr, David		16,317		52,417		*
Higgins, Gregory		50,000		79,098		*
Hirschhorn, Warren		28,890		38,697		*
Hoemke, Carl R.E.		26,326		63,448		*
Jacobs, Jonathan		18,111		51,322		*
Janssen, Christopher		7,255		51,438		*
Jeffrey Chanin & Co.,		37,180		-		-
Jensen, Patrick		6,707		32,649		*
Katz, Kevin		802		25,536		*
Kernick, Glen Noll		12,989		38,112		*
Kirtley, Robert		20,000		67,084		*
Kramer, Mark		1,742		18,210		*
La Greca, Frank		19,055		27,775		*
Larsen, David		10,453		36,766		*
Lee, Edward		12,989		24,056		*
Levin, Nathan I.		4,000		42,342		*
Levitske, John		9,912		5,596		*
Lilly, John, Strategic Insights, LLC		3,969		421		*
Lloyd, Michael		14,674		13,314		*
Lynch, Michael		18,910		31,673		*
MacMullan, Daniel		26,838		28,257		*
Madden, John		11,909		14,756		*
Magnan, Yann		1,304		6,791		*
Marcinkowski, Myron A.		45,542		29,070		*
Martinez, Carlos		6,868		12,056		*
Massey, James		10,424		11,763		*
May, Bryce		2,784		-		-
May, Richard		27,394		-		-
Melrose, Geoffrey		10,184		19,519		*
Miscione, John		8,288		10,076		*
Mondello, Mark T.		10,495		12,399		*
Newman, Raphael		42,083		31,146		*
O'Brien, John		348		11,443		*
Osswald, John		6,160		26,148		*
Pfeiffer, Allen		42,083		69,820		*
Phili, Kleanthis		42,083		94,681		*
Ploussard, Jeffrey J.		13,707		30,883		*
Prendergast, Patrick		14,817		12,040		*
Price, Dean		1,933		6,752		*
Prindle, Ross		42,083		56,320		*
Puzzuoli, Patrick		806		34,179		*
Rubin, Mark		25,701		3,263		*
Sacks, Jeremy L.		18,031		16,290		*

S-4

	Shares
	Offered		Class A Common Stock
	Hereby		on a Fully-Exchanged Basis(1)
Selling Stockholders	Number		Number		Percent(2)
Saltzman, Sherri		2,738		7,794		*
Schiedemeyer, Jeffrey		7,802		65,345		*
Schumacher, Mathias		1,933		48,002		*
Sebastian, Steve		1,854		-		-
Seery, Mike		8,390		-		-
Shanker, Steven J.		42,083		37,893		*
Shanley, Margaret		3,484		23,681		*
Snel, Jan Jaap		3,398		10,521		*
Spieler, David A.		10,000		82,667		*
Tanner, Matthew		1,933		8,365		*
Turf, David		7,802		24,025		*
Victor, Skip, Trust,		114,948		114,948		*
Viscio, Paul		18,031		27,633		*
Vitti, Michael		762		24,208		*
Wabnitz, Michael		1,334		15,269		*
Weaver, Tab		3,222		78,543		*
Wierwille, Michael C.		3,288		39,623		*
Williams, Brent		12,590		14,013		*
Wisler, Philip		12,989		38,598		*

____________________

*	Less than 1%.

(1)

Assumes that each selling stockholder sells all of its shares of Class A common stock offered pursuant to this prospectus and neither acquires nor disposes of any other shares, or right to purchase other shares, of our Class A common stock subsequent to the date as of which we obtained information regarding its holdings. The selling stockholders are not obligated to sell all or any portion of the shares of our Class A common stock, and the number and percentage of shares of Class A common stock owned after the offering will depend on the number of shares actually sold.

(2)	Based on a total of 40,999,934 shares of Class A common stock outstanding as of November 11, 2010 on a fully-exchanged basis.

(3)	Also includes 11,215 New Class A Units held by Mr. Creagh through Vestar/D&P Holdings, LLC.

S-5