## PV & FV of Periodic Uneven Cash Flows & Rates

I am just fooling around with cash flows at this point. My last post was “PV & FV of Periodic Uneven Cash Flows, where I showed an easy way to enter cash flows that changed for different periods of time. I thought it might save time over entering all the cash flows separately. I am not going […]

## PV & FV of Periodic Uneven Cash Flows

In the last post we looked at graduated annuities, where the cash flow changes at a given rate. Imagine you need the present value of an annuity with a cash flow that changes unevenly and that change stays the same for certain periods. Take for example the cash flow below: Here we have a 10-year annuity that pays \$1,000 each month for […]

A graduated annuity is like a regular annuity, except instead of getting the same cash flow each period, the cash flow grows at a given rate throughout the term. There a two basic types of graduated annuities, ordinary annuities (cash flow comes at the end of each period), and annuities due (cash flow starts at the beginning of each […]

## Approximating Duration, Modified Duration, and Convexity with Option Free Bonds

The use of Excel’s PRICE function can eliminate much of the math required to understand how modified duration and convexity can be used to predict the price change in option-free bonds. The spreadsheet for this post is called “Option Free” and like all of my spreadsheets, it can be downloaded for free. The sheet is […]

## 30/360 Present and Future Values with Dates

In my very first post back in August of last year titled “No XNFV Excel Function?” I showed formulas for calculating present value and future values when cash flows with dates are given. These formula were calculated based upon actual days between dates and a 365 day base year. I lamented that Excel has a function that calculates present values with dates […]

## Amortization Consolidation

If you have looked at very many of my posts and spreadsheets, it is obvious that a good deal of them involve loan amortization schedules. So does this one. The first sheet in the workbook “consolidate” is called “Amortization Loan”. That is because it contains a standard monthly amortizing loan schedule. There are times when […]

## Solve for a target net worth ratio

Math majors can skip this one. I found it looking through my files and thought it might be useful to some credit union financial managers. The math problem is: How much of a change in capital would it take to move the net worth ratio from the current level, to another level. At first glance it seems […]

## Simple Interest

Both Child Support #1 and #2 have been simplified in order to correct a problem which includes the prepayment of support. This results in the payer earning the stated interest rate on the positive balance prepaid, which is typically much higher than market rates, and may not be allowed in some jurisdictions. Although there are […]

## Mortgage Pool – Holding Period Return

This spreadsheet was originally compiled to help make the decision to either sell mortgages that were originated, or keep them. It can also be used to help with the decision to purchase a pool of whole loans, or a securitized mortgage pools. Two different concepts of return are referred to in this post. The two are […]

## Build your own CPR model

Last November I posted an amortization spreadsheet that allowed for variable interest rates on mortgages. I used that spreadsheet and added a CPR variable. That way you can create your own CPR model, rather than using one CPR for the full term or using the PSA model. The default numbers above show the user wants interest rates […]

## Effective Duration – No VBA or Amortization

Back in October I showed how to calculate effective duration and convexity on a pool of fixed rate mortgages with the help of amortization schedules. In November I posted a formula that could calculate the price of a fixed rate pool of mortgages, including the use of CPR and servicing, in one cell. That same month I […]

## California Home Prices Dashboard

The California Association of Realtors® (CAR) publishes monthly home price data for each county in California. I produced a dashboard using their data and the 2010 census for income and population data. In order to keep the dashboard up to date, the “All Counties” sheet stores the data from CAR. There is a link to […]