JOINT FILING AGREEMENT
Exhibit 1
In accordance with Rule 13d-1(f) under the Securities Exchange Act of 1934, the undersigned
hereby (i) agree to the joint filing with all other Reporting Persons (as such term is defined in
the statement on Schedule 13D described below) on behalf of each of them of a statement on
Schedule 13D (including amendments thereto) with respect to the Common Stock, par value $0.01 per
share, of Duff & Xxxxxx Corporation and (ii) agree that this Agreement be included as an Exhibit to
such joint filing. This Agreement may be executed in any number of counterparts all of which taken
together shall constitute one and the same instrument.
Dated: October 12, 2007
| VESTAR CAPITAL PARTNERS IV, L.P. | ||||||
| By: | Vestar Associates IV, L.P., | |||||
| its General Partner | ||||||
| By: | Vestar Associates Corporation IV, | |||||
| its General Partner | ||||||
| By: | /s/ Xxxxxx Xxxx | |||||
| Name: Xxxxxx Xxxx | ||||||
| Title: Managing Director | ||||||
| VESTAR/D&P HOLDINGS LLC | ||||||
| By: | Vestar Capital Partners IV, L.P., | |||||
| its Managing Member | ||||||
| By: | Vestar Associates IV, L.P., | |||||
| its General Partner | ||||||
| By: | Vestar Associates Corporation IV, | |||||
| its General Partner | ||||||
| By: | /s/ Xxxxxx Xxxx | |||||
| Name: Xxxxxx Xxxx | ||||||
| Title: Managing Director | ||||||
| VESTAR ASSOCIATES CORPORATION IV | ||||||
| By: | /s/ Xxxxxx Xxxx | |||||
| Name: Xxxxxx Xxxx | ||||||
| Title: Managing Director | ||||||
| VESTAR ASSOCIATES IV, L.P. | ||||||
| By: | Vestar Associates Corporation IV, | |||||
| its General Partner | ||||||
| By: | /s/ Xxxxxx Xxxx | |||||
| Name: Xxxxxx Xxxx | ||||||
| Title: Managing Director | ||||||
