One of my calculator-collecting interests is special-purpose calculators, and among those, calculators preprogrammed for business and finance calculations are probably the most numerous.  And once again, we kick things off with the best (and others) from Texas Instruments.

1. TI Business Analyst: The top "Compute" line allows calculations of annuity values; the lower one handles cost analysis.  "Compute" to the side handles linear regression.  The foundation of a long-running series.
2. TI Business Analyst I: Same functions as the Business Analyst in a different-looking package.

1. TI Money Manager: We've seen these functions before...
2. TI-MBA: An upgrade from the others, this one combines the financial functionality of the BA line with the (admittedly limited) programmability of the TI-55.

1. BA-35 Student Business Analyst, version 1. The traditional business functions are bundled into a calculator designed for and marketed to business students.
2. BA-35 Student Business Analyst, version 2.  A slightly different case design houses the essential business functions.  (A third version, in a black case, exists.)

1. TI BA II-Plus/Advanced Business Analyst.  Original version, circa 1991.
2. TI BA-III/Executive Business Analyst
3. TI BA II Plus: This is a streamlined version of the Advanced Business Analyst, circa 2000.

1. TI-BA-35 Solar:
2. TI-BA-55:  Like the MBA, this one is also programmable.

1. Business Edge: Just pulled out of darkness for the photograph--the net result is that the entire LCD display is visible at once.  The five rectangles at the bottom of the screen are touch-sensitive keys which can be set to perform four functions each by using the red keys.
2. BA-20: This inexpensive business calculator is degined as a small desktop machine and also includes a clock.

These two TI gems would both be classified as "tough to find" on the collectors' market.

BA Real Estate: This model is a favorite among real estate professionals and calculator collectors alike.  Note well the "000" key at the lower left for ease in entering large numbers.
Personal Banker: This notebook-format calculator opens to display a panel of 7 redefinable keys on the right side.  Four worksheets guide the user through entering data for common financial calculations.  This format was also used by TI with the SC-10 scientific calculator.

Financial Investment Analyst: The most intricate TI financial calculator, this one works in a modified spreadsheet format with some alphanumerics in the display.  The redefinable keys at the upper right were a feature of the TI-5x programmable calculator line, and the large screen is a precursor of the TI-8x line of graphing calculators

Fixed Income Securities: This reworked Financial Investment Analyst can be used for financial calculations involving US Treasury and municipal bonds, corporate securities, and much more.  This calculator also uses a modified spreadsheet format.

The Allianz calculator is a specialized TI-58, customized for insurance calculations and used in Germany by employees of the Allianz company.  The revamped keyboard combined with a customized ROM chip facilitated quick computation of significant insurance quantities.

And, of course, the obligatory tip of the hat to non-Texas Instruments products:

1. Calculated Industries Financial II: Also known as the Loan Arranger, which is a much cooler name.
2. Novus Financier
3. Novus Financier PR: Like the Financier, but adds limited programmability.