December 16, 2005 OFC. Ge is.

Ms. Jean A. Webb

Secretary

Commodity Futures Trading Commission
Three Lafayette Center

1155 21 Street, NW.

Washington, DC 20581

Reference File #2617.01
Rule Certification

Dear Ms. Webb:

Pursuant to Commission Regulation 40.6(a), the Chicago Board of Trade (CBOT®) hereby
submits the following:

- Extend, through December 31, 2006, the designation of 10-Year and 5-Year
Interest Rate Swap futures and futures options for trading pursuant to
existing Regulation 331.05 (copy attached), at the established minimum size
threshold of 2,000 contracts on an outright basis.

This extension will continue a pilot program previously scheduled to expire as of December 31,
2005.

There were no opposing views concerning this program extension.

The CBOT certifies that this program extension complies with the Commodity Exchange Act
and the rules thereunder.

Sincerely,

Paul J. Draths
Vice President and Secretary

b121305



331.05 Block Trade Transactions - The Board of Directors may designate any contract initially
listed for trading on or after December 31, 1999 as eligible for Block Trade transactions under this
Regulation 331.05 and shall determine the minimum size thresholds for the contracts in which Block
Trade transactions are permitted. In determining the minimum size threshold, the Board of Directors shall
take into consideration (to the extent available) the size distribution of transactions in the contract, the
size distribution of transactions in the related cash or over-the-counter markets, and all other information
relevant to transaction size in the relevant contract. The hours of operation of the Block Trade facility
shall be determined by the Board of Directors.

Members may enter into transactions outside of the Exchange's central markets, at prices mutually
agreed, with respect to contracts that have been designated by the Exchange for such purpose, provided
that the following conditions are satisfied:

a) Each buy or sell order underlying a Block Trade must (i) state explicitly that it is to be, or may
be, executed by means of a Block Trade and (ii) be at least for the minimum transaction size
as determined by the Board of Directors. Orders may not be aggregated in order to achieve
the minimum transaction size.

b) The price at which a Block Trade is executed must be fair and reasonable in light of (i) the
size of such Block Trade; (ii) the price and size of other trades in the same contract at the
relevant time; and (iii) the price and size of trades in other relevant markets, including
without limitation the underlying cash market or other related futures markets, at the relevant
time. The price at which a Block Trade is executed shall not affect conditional orders such
as limit orders or stop orders. The price at which a Block Trade is executed shall not be
used in establishing settlement prices.

c) Each nonmember customer to a Block Trade transaction must qualify as an “eligible contract
participant’, as that term is defined in Section 1a(12) of the Commodity Exchange Act,
provided that, if any Block Trade is entered into on behalf of customers by a commodity
trading advisor registered under the Act, including without limitation any investment advisor
registered as such with the Securities and Exchange Commission that is exempt from
regulation under the Act or Commodity Futures Trading Commission Regulations
thereunder, or a foreign person performing a similar role or function subject as such to
foreign regulation, with total assets under management exceeding $50 million, the individual
customers need not so qualify.

d) Each Block Trade executed pursuant to this Regulation must be cleared through the clearing
members. Information identifying the relevant contract, contract month, price, quantity, time
of execution and counterparty clearing member for each Block Trade must be reported to the
Exchange within five minutes immediately following execution of such Block Trade. The
Exchange will publicize information identifying the trade as a Block Trade and identifying the
relevant contract, contract month, price, and quantity for each Block Trade immediately after
such information has been reported to the Exchange.

e) Each clearing member and member that is party to a Block Trade shall record the following
details on its order ticket: the contract (including the delivery or expiry month) to which such
Block Trade relates; that the trade is a Block Trade; the number of contracts traded; the
price of execution; the time of execution; the identity of the counterparty; and, if applicable,
details regarding the customer for which the Block Trade was executed. Upon request by
the Exchange, such clearing member or member shall produce satisfactory evidence,
including without limitation the order ticket referred to in the preceding sentence, that the
Block Trade meets the requirements set forth in this Regulation. (09/01/03)