Adding Price Information to Beancount

Once you’ve recorded some transactions with stocks, the price of those stocks changes over time. Ideally, running bean-report ledger.beancount networth would take into account the current prices of your assets, as opposed to being limited to the price of the assets as entered on the transaction date. The price directive allows for this. It’s simple to use:

2022-08-29 price VTSAX 98 USD

That’s it. Add price directives whenever you want. But it’s even easier than that! Most directives in beancount support meta attributes. An important one is the price attribute for a commodity, which will allow you to use a tool called bean-price (included with beancount), to look up prices automatically. It supports several providers, but a common choice is Yahoo:

2022-01-01 commodity VTSAX
  price: "USD:yahoo/VTSAX"

Now you can run bean-price:

% bean-price ledger.beancount
2022-08-29 price VTSAX                                  98 USD

You can redirect this output directly to a beancount file:

% bean-price ledger.beancount >> ledger.beancount

The tool will (be default) take into account existing price entries, and be idempotent. So running hte above command twice will not add two price directives to your file.