Constant Default Rate (CDR)

Also see this post: Comparing CDR Default Formulas to Industry Standard Default Formulas   Constant Default Rate (CDR) is an annualized rate of default on a pool of loans. The default rate on loans depends on a number of conditions, such as the age of the loans, seasonality, burnout levels, FICO, LTV, income, etc. Since […]

Convert CPR, SMM & ABS (APS)

We have already discussed Constant Prepayment Rate (CPR) and Single Monthly Mortality Rate (SMM). Another prepayment rate is the Absolute Prepayment Speed (APS), used mostly for  securities backed by auto, truck, and RV loans. The acronym for Absolute Prepayment Speed (APS) is also referred to as ABS, which is confusing because ABS is also the acronym for Asset-Backed […]

Solve for Last Payment Due

In my first blog post back in August, I had a formula that would solve for future value given dates and amounts. In this post we will use the same formula to solve for the last payment due. There are a number of scenarios where the last payment might be needed. Assume for a moment that you won a court judgment […]

Reverse Engineering Constant Prepayment Rate (CPR)

This post has been updated in a new post called Calculating Historic CPR. The spreadsheets has also been updated “CalCPR.xlsm” After you review this post, please see the updated post. Unless you work for a firm that packages pools of mortgages, you will probably never need to calculate the historic CPR on an existing pool. Even so, […]

Mortgage Pool Price and Average Life One Cell Formulas

See updated formula at: MBS Math Formula. Servicing, CPR, Payment Delay, Default Rate & Loss Severity http://pistulka.com/Other/?p=2384 A few posts back I showed the “megaformula” I used back in the day for calculating the price of a mortgage pool with prepayments (CPR). Rather than treating the one cell formula as just an interesting antique, I […]

Amortization Schedule With Variable Rates

Note: I have updated this post with more options. See Variable Rate Amortization – Day/Year Count & Last Payment Options. Have you ever wanted an amortization schedule where you can set the rate for one term and then change the rate for another term, and change the rate and term a total of six times? […]

Mortgage Backed Securities (MBS) “MegaFormula”

See updated formula at: MBS Math Formula. Servicing, CPR, Payment Delay, Default Rate & Loss Severity http://pistulka.com/Other/?p=2384 This post is just to show you 20-somethings what we had to go through to calculate the price of a mortgage backed security back in the day. I had the first desktop computer (before Apple and Radio Shack were […]

Bonus Checking

To understand this next spreadsheet, you have to take your accounting hat off and put your financing hat on. Consider all your sources of funding; savings accounts, money market accounts, CDs, borrowing, and checking accounts. There may be more, but considering the above, checking accounts will always be the cheapest source of funds. The reason […]

Macaulay Duration Plus Balloon Payment

I was asked by a reader to add an option to the workbook “MacaulayDuration”. The option is to include a balloon payment. I added the option in a separate workbook called “MacaulayDuration_with_Balloon”. Read my post on “Macaulay Duration of an Amortizing Loan” for further information. Download “MacaulyDuration_with_Balloon” from: http://www.pistulka.com/Excel_Shared/ Downloads Written in Excel 2013

APR – Adjustable Rate Mortgage (ARM)

Like the previous post this worksheet calculates the APR, but for an adjustable rate mortgage or ARM. The difference between the fixed rate and the ARM is that the ARM cash flow is based upon reaching the fully-indexed rate, given the information available when the loan was made, and assumes it stays at the fully-indexed rate for the remaining term of the […]

APR – Fixed Rate Mortgage

Given the inputs in yellow cells, check boxes and option buttons, this sheet uses an amortization schedule to calculate APR (or APY) for a fixed rate mortgage. Both Loan Balance and Interest Rate need no explanations. Truth in Lending Fees are additional dollar costs to the borrower to acquire the loan. Points represent a percent of […]