Here are some Emacs things relating to finance, money, accounting, etc.

* LedgerMode -- double entry accounting.
* BeancountMode -- Emacs major-mode to work with Beancount ledger files.
* BeancountTxnElisp -- A Beancount txn parser and writer, implemented in EmacsLisp.
* BalanceMode -- tracking bank accounts.
* LoanPaymentCalculator -- calculating loan payments.
* [[Chart]] -- stock and commodity quotes in Emacs.
* StockQuote -- stock quotes using UrlPackage.
* [http://user42.tuxfamily.org/accjournal/index.html accjournal.el] -- text file double-entry accounting.
* [http://www.moge.org/okabe/docs/elisp.html accounting.el] -- trial balance from entries in a buffer ([http://www.moge.org/okabe/temp/accounting.el download] at end of page)
* FormTenForty -- US Income tax table

Also of interest,

* CategoryCalculators
* CsvMode -- edit CSV files
* SpreadSheet -- spreadsheets in Emacs.