Exhibit (l) under Form N-1A Exhibit 99 under Item 601/Reg SK FEDERATED MDT SERIES Federated Investors Funds 5800 Corporate Drive Pittsburgh, Pennsylvania 15237-7000 August 8, 2006 Federated MDTA LLC 125 Cambridge Park Drive Cambridge, MA 02140 Dear...

                                              Exhibit (l) under Form N-1A
                                         Exhibit 99 under Item 601/Reg SK


                              FEDERATED MDT SERIES

                            Federated Investors Funds
                              0000 Xxxxxxxxx Xxxxx
                       Xxxxxxxxxx, Xxxxxxxxxxxx 00000-0000

                                 August 8, 2006


Federated MDTA LLC
000 Xxxxxxxxx Xxxx Xxxxx
Xxxxxxxxx, XX 00000


Dear Sir or Madam:

      Federated MDT Series (the "Trust") hereby accepts your offer to purchase
4,000 shares at a price of $25.00 per share for an aggregate purchase price of
$100,000.00. This agreement is subject to the understanding that you have no
present intention of selling or redeeming the shares so acquired.



                                                Very truly yours,


                                                Federated MDT Series


                                                By:________________________



Accepted:

Federated MDTA LLC

By:________________________