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Tag Archives: Math
Fast Formulas #6: Finding the Time
The Fast Formulas on this blog provide shortcut calculations for financial instruments such as mortgages and bonds. Most formulas involve the symbol n to represent the number of periods (e.g. years or months) until the end of the instrument. Usually … Continue reading
Posted in Bonds, Fast Formulas, Math
Tagged Bond Math, Fast Formulas, Math, Mortgage Math, Time Value of Money
2 Comments
Fast Formulas #4: Geometric Series (One of the Tricks)
In Fast Formulas #3: Pool Average Life with CPR Prepayments, I presented Formula 3.1, a shortcut calculation for the average life of a loan pool under a constant prepayment assumption. I mentioned that Formula 3.1 was derived by using “a … Continue reading
Posted in Fast Formulas, Math
Tagged David Hilbert, Fast Formulas, Geometric Series, Math, Matt Henderson
5 Comments
Fast Formulas #3: Pool Average Life with CPR Prepayments
Fast Formulas #2: Average Life of Mortgage (Amortizing with Balloon) presented a compact formula for calculating the average life of a mortgage that pays as scheduled until it is paid off with a “balloon” payment before the scheduled end of its term. It occurred to … Continue reading
Fast Formulas #2: Average Life of Mortgage (Amortizing with Balloon)
Fast Formulas #1: Average Life of Mortgage (as Scheduled) showed a quick way to calculate the weighted average life (“WAL”) of a fixedrate mortgage that pays as originally scheduled. I found this formula (which is probably not original) by substituting the standard level … Continue reading
Posted in Fast Formulas, Math
Tagged Average Life Formula, Closed Formula, Fast Formulas, Financial Math, Loan Average Life, Math, Weighted Average Life
12 Comments
Fast Formulas #1: Average Life of Mortgage (as Scheduled)
The weighted average life (“WAL”) of a mortgage is the average time until principal is repaid. It is also the average amount of time that the principal is outstanding. Recall that for a standard fixedrate mortgage with level payments, the principal … Continue reading
Posted in Fast Formulas, Math
Tagged Average Life Formula, Closed Formula, Fast Formulas, Financial Math, Loan Average Life, Math, Weighted Average Life
9 Comments
Puzzle #4: Bond Pricing
Here’s another puzzle I’ve used to teach bond math. It’s not hard, but it requires some understanding of bond concepts that I will explain as we go (I beg the patience of bond mavens). Suppose you are the financial advisor … Continue reading
Posted in Bonds, Fun, Math, Puzzles
Tagged Bond Math Puzzle, Callable Premium Bonds, Finance Math Puzzle, Financial Math, Math, Price to Call, Price to Maturity, Puzzle, Puzzle #4, Yield to Maturity
12 Comments
Puzzle #3: A Better Answer
Puzzle #3 asked for the weighted average life (“WAL”) of the principal payments for a 30year mortgage that is cut short by a balloon payment at 15 years. The following information was provided: $100,000 Principal; 5% Interest Rate; $536.82 Level … Continue reading
Posted in Fun, Math, Puzzles
Tagged Average Life Formula, Cool Graphs, Finance Math Puzzle, Financial Math, Math, Puzzle, Puzzle #3, Weighted Average Life
5 Comments