SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 SCHEDULE 13G (RULE 13d-102) INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT TO RULES 13d-1(b), (c) AND (d) AND AMENDMENTS THERETO FILED PURSUANT TO RULE 13d-2(b) (Amendment No. __2___)* Rush Enterprises, Inc. (Name of Issuer) Class B Common Stock - -------------------------------------------------------------------------------- (Title of Class of Securities) 781846308 - -------------------------------------------------------------------------------- (CUSIP Number) 12/31/2005 - -------------------------------------------------------------------------------- (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to which this Schedule is filed: [X] Rule 13d-1(b) [ ] Rule 13d-1(c) [ ] Rule 13d-1(d) *The remainder of this cover page shall be filled out for a reporting person's initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page. The information required in the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 or otherwise subject to the liabilities of that section of the Act, but shall be subject to all other provisions of the Act (however, see the Notes).
CUSIP NO. 781846308 13G PAGE 2 OF 5 PAGES - -------------------------------------------------------------------------------- Names of Reporting Persons I.R.S. Identification Nos. of Above Persons (Entities Only) Munder Capital Management - -------------------------------------------------------------------------------- 2 Check the Appropriate Box if a Member of a Group (a) [ ] (See Instructions) (b) [ ] - -------------------------------------------------------------------------------- 3 SEC Use Only - -------------------------------------------------------------------------------- 4 Citizenship or Place of Organization State of Delaware - -------------------------------------------------------------------------------- Number of 5 Sole Voting Power Shares 1,303,437 ----------------------------------------------------- Beneficially 6 Shared Voting Power 0 Owned by ----------------------------------------------------- 7 Sole Dispositive Power Each 1,314,487 ----------------------------------------------------- Reporting 8 Shared Dispositive Power Person With 0 - -------------------------------------------------------------------------------- 9 Aggregate Amount Beneficially Owned by Each Reporting Person 1,314,487 - -------------------------------------------------------------------------------- 10 Check if the Aggregate Amount in Row (9) Excludes Certain Shares [ ] (See Instructions) - -------------------------------------------------------------------------------- 11 Percent of Class Represented by Amount in Row (9) 17.0% - -------------------------------------------------------------------------------- 12 Type of Reporting Person (See Instructions) IA - --------------------------------------------------------------------------------
CUSIP NO. 781846308 13G PAGE 3 OF 5 PAGES Item 1. (a) Name of Issuer: Rush Enterprises, Inc. (b) Address of Issuer's Principal Executive Offices: 555 I.H. 35 South, Suite 500 New Braunfels, Texas 78130 Item 2. (a) Name of Person Filing: Munder Capital Management ("Munder") (b) Address of Principal Business Office: Munder Capital Center 480 Pierce Street Birmingham, MI 48009 (c) Citizenship: Munder is a general partnership formed under the laws of the State of Delaware (d) Title of Class of Securities: Class B Common Stock (e) CUSIP Number: 781846308 Item 3. If this statement is filed pursuant to Rule 13d-1(b), or 13d-2(b), check whether the person filing is a: /X/ (e) an investment adviser in accordance with Rule13d-1 (b)(1)(ii)(E)
CUSIP NO. 781846308 13G PAGE 4 OF 5 PAGES Item 4. Ownership (a) Amount Beneficially Owned: 1,314,487 shares (the "Common Stock") (b) Percent of Class 17.0% (c) Number of shares as to which such person has: (i) sole power to vote or direct the vote: 1,303,437 (ii) shared power to vote or direct the vote: 0 (iii) sole power to dispose or to direct the disposition of: 1,314,487 (iv) shared power to dispose or direct the disposition of: 0 Item 5. Ownership of Five Percent or Less of a Class Not Applicable. Item 6. Ownership of More than Five Percent on Behalf of Another Person While Munder is the beneficial owner of the shares of Common Stock of the Company, Munder is the beneficial owner of such stock on behalf of numerous clients who have the right to receive and the power to direct the receipt of dividends from, or the proceeds of the sale of, such Common Stock. One client, The Munder Small-Cap Value Fund has the right to receive and the power to direct the receipt of dividends from, and the proceeds from the sale of, more than 5% of the common stock (6.4%) of the Issuer. The Munder Small-Cap Value Fund is a separate series of Munder Series Trust, an open-end registered investment company under the Investment Company Act of 1940.
CUSIP NO. 781846308 13G PAGE 5 OF 5 PAGES Item 7. Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company Not Applicable. Item 8. Identification and Classification of Members of the Group Not Applicable. Item 9. Notice of Dissolution of Group Not Applicable. Item 10. Certification By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired in the ordinary course of business and were not acquired for and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect. SIGNATURE After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct. MUNDER CAPITAL MANAGEMENT, a Delaware general partnership By: /s/ Mary Ann C. Shumaker Dated: 3/27/2006 Its: Associate General Counsel