Today is Class A Notification Day in the Secondary Mortgage Market. Class A MBS coupons consist of Fannie Mae and Freddie Mac 30 year loan notes.

The July FN 4.5 MBS coupon has begun the settlement process and it's price seems to haven fallen fast!


The MBS coupons that determine rate sheet pricing are traded in the TBA MBS market.

TBA = To be Announced

In the TBA MBS market, at the time a trade is made, buyers and sellers agree to a few specific terms like what coupon, the issuing agency (Fannie, Freddie, Ginnie), size of trade, and a buy/sell price....the actual pools of loans are NOT exchanged at the time of this commitment. Instead, the MBS buyer and the seller make an agreement to complete the transaction at a later date. In the MBS market this date is pre-determined; it is called SETTLEMENT DAY (clever name huh?).

Agency MBS trading settles once a month.  We can actually watch forward pricing as much as three months ahead.

Two days before the pre-scheduled settlement date, the MBS seller "notifies" the MBS buyer of the specific pools that they will deliver to satisfy the previously agreed upon terms of the trade.

This is Fannie Mae's guidance

Forty-eight hours prior to settlement, pool information must be communicated to the Capital Markets Sales Desk's back office by phone (202-752-5384), facsimile (202-752-3439), or via EPN transmission. Delivery of pool information must take place by 3:00 p.m. eastern time. It is advisable that pool information is communicated early as phone lines, fax machines, and the EPN queues are extremely taxed as the 3:00 p.m. deadline approaches. If the transmission does not occur by 3:00 p.m., one day's fail will be incurred, despite the fact the information is residing in queue.

Then the MBS buyer reviews the pool information to ensure the seller has delivered loans that meet the agreed upon terms.  48 hours later, after being deemed to within "Good Delivery" guidelines, pool purchase funds are wired and the trade is complete (it goes deeper...this is the outline).


Today the front month is the July delivery coupon and the back month is the August coupon. Tomorrow the front month delivery coupon will be the August coupons and back month will be September.

Prices don't really fall. We just start watching the back month MBS coupon because the front month coupon has just begun the settlement process.  The back month coupon price remains the same!

Below is the current August settlement FN 4.5 MBS coupon. It's bid at 103-17. This is where prices will "seem" to have fallen in the chart above...


The main reason behind the price "DROP" is lost "time value of money".

Interest rates can be thought of in three ways..

  1. Required Rate of  Return: this is the minimum amount of return an investor is willing to receive when making an investment.
  2. Discount Rate: the rate used to determine the present value of future cash flows. When you loan someone money with the intention of being paid back in the future, you must place a value on how much of a premium you are losing by not spending that money right now. The discount rate is essentially how much you are charging to delay repayment until a future date.
  3. Opportunity Cost: the value an investor passes up when choosing an alternate investment. You must earn enough interest when you loan someone money to compensate for the loss of income that you could have been earning by investing elsewhere.

LET ME POSE A QUESTION: Would you rather have $1.00 today or $1.00 tomorrow?

You would rather have $1.00 today! If you have $1.00 today you can invest it today...the fact you are investing today vs. tomorrow implies you are giving the asset more time to appreciate, more time to accumulate interest earned (ACCRUE).

To relate this concept to the MBS market---if you buy the July FN 4.5 coupon, then your returns will begin accruing on July 1. If you buy the August coupon---your returns don't start accruing until August 1. That means you would have to wait 19 days (from today) for your money to start working for you.  Investing now, before the roll,  puts money to work now, or in today's case, on July 1.

Starting tomorrow, because the July coupon has already entered into the settlement process, MBS investors will have to wait until August 1 to see their funds start working. To compensate for the lost Time Value of Money, investors demand higher MBS yields. This lost time value of money is represented  by lower back month MBS prices (in this case the August FN 4.5 coupon).

Note: to be clear, the previous owner has rights to the income (accrued interest) earned from while they owned the coupon. The price you pay to purchase the back month coupon includes the income the current owner has accrued while they owned the coupon. The buyer recovers the added premium when  the coupon payment is deposited in their account. This is called the 'clean price''s the same way Treasuries trade.

Plain and Simple:
  If you own the July FN 4.5 MBS coupon, then you are entitled to the coupon clips (income) paid in July. If you decided to wait and buy the August MBS coupon...then you have to wait until August for your investment to start accruing interest. To compensate for the lost "time value of money", investors demand higher yields, which is why prices fall when delivery rolls from front month to back month. (not including any profit earned from price movement)

This explains why 60 and 90 day locks are more expensive. The longer the lock commitment period, the more it costs the lender to hedge interest-rate volatility and fall out risk.


You won't notice the affects tomorrow. Lenders have been building loan pricing based on the August coupon for several weeks already, that's why I've been discussing the August coupon since early June.   Lenders must roll earlier because secondary desks are lower in the MBS supply chain and must deliver their closed loans to investors with enough time to allow for post-closing/pre-purchase review.

Here is an example of a delivery schedule.

I'll probably roll forward to the September delivery Class A MBS coupon in the next few days.