Price Annotations

Overview

Price annotations record the market exchange rate at the time of a transaction. Unlike cost specifications, prices are informational and typically don't affect transaction balancing when a cost is also present.

Syntax

price_annotation = "@" amount      ; Per-unit price
                 | "@@" amount     ; Total price

Price Types

Per-Unit Price @

Specifies the price per unit:

; 100 EUR at 1.10 USD each
Assets:EUR  100 EUR @ 1.10 USD

Total Price @@

Specifies the total price for all units:

; 100 EUR for 110 USD total
Assets:EUR  100 EUR @@ 110 USD

Per-unit price is computed as: 110 / 100 = 1.10 USD

Weight Calculation

Price Without Cost

When only a price annotation is present (no cost spec), the price determines the posting weight:

2024-01-15 * "Currency exchange"
  Assets:EUR   100 EUR @ 1.10 USD    ; Weight: 100 × 1.10 = 110 USD
  Assets:USD  -110 USD               ; Weight: -110 USD
  ; Transaction balances in USD

Price With Cost

When both cost and price are present, the cost determines the weight (price is informational):

2024-01-15 * "Sell stock"
  Assets:Stock  -10 AAPL {150 USD} @ 185 USD
  ; Weight: 10 × 150 = 1500 USD (uses cost, not price)

  Assets:Cash   1850 USD              ; Weight: 1850 USD
  Income:CapitalGains  -350 USD       ; Weight: -350 USD
  ; Balances: 1500 - 1850 + 350 = 0 ✓

The @ 185 USD records that AAPL was trading at $185 but doesn't affect balancing.

Implicit Price Generation

Transactions with price annotations can generate implicit price entries using the implicit_prices plugin:

plugin "beancount.plugins.implicit_prices"

2024-01-15 * "Exchange"
  Assets:EUR  100 EUR @ 1.10 USD
  Assets:USD

; Plugin generates:
; 2024-01-15 price EUR 1.10 USD

This populates the price database for later valuation.

Note: There is no option for this - it requires loading the beancount.plugins.implicit_prices plugin.

Currency Conversion

Simple Exchange

2024-01-15 * "Buy Euros"
  Assets:EUR   1000 EUR @ 1.0875 USD
  Assets:USD  -1087.50 USD

With Fees

2024-01-15 * "Exchange with fee"
  Assets:EUR      1000 EUR @ 1.09 USD
  Expenses:Fees     5.00 USD
  Assets:USD    -1095.00 USD

Triangular Conversion

; EUR → GBP via USD rates
2024-01-15 * "EUR to GBP"
  Assets:EUR  -1000 EUR @ 1.10 USD
  Assets:GBP    850 GBP @ 1.2941 USD
  ; EUR: 1000 × 1.10 = 1100 USD
  ; GBP: 850 × 1.2941 = 1100 USD
  ; Balances!

Price vs. Cost

Aspect	Cost {...}	Price @
Purpose	Track acquisition basis	Record market rate
Creates lots	Yes	No
Affects weight	Always	Only without cost
For reductions	Matches existing lots	Informational only
Capital gains	Determines basis	Records sale price

Combined Example

2024-01-15 * "Buy stock"
  Assets:Stock  10 AAPL {150 USD}     ; Cost: creates lot at 150
  Assets:Cash  -1500 USD

2024-06-15 * "Sell at profit"
  Assets:Stock  -10 AAPL {150 USD} @ 185 USD
  ; Cost {150 USD}: matches lot, weight = 1500 USD
  ; Price @ 185 USD: records market price (informational)

  Assets:Cash   1850 USD
  Income:CapitalGains  -350 USD       ; Gain: (185-150) × 10

Total Price Precision

Total price (@@) avoids rounding issues:

; Per-unit: may have rounding
Assets:Stock  7 AAPL @ 185.714285 USD

; Total: exact amount
Assets:Stock  7 AAPL @@ 1300 USD
; Per-unit computed: 1300 / 7 = 185.7142857...

Price Direction

Prices are always "base @ quote":

; 1 EUR = 1.10 USD
Assets:EUR  100 EUR @ 1.10 USD

; 1 USD = 0.91 EUR (inverse)
Assets:USD  100 USD @ 0.91 EUR

Both express the same exchange rate from different directions.

Examples

Stock Sale with Gain

2024-06-15 * "Sell Apple stock"
  Assets:Brokerage  -50 AAPL {150.00 USD} @ 195.50 USD
  Assets:Cash       9775.00 USD
  Income:CapitalGains:Long

Currency for Travel

2024-03-01 * "Get travel money"
  Assets:Cash:EUR   500 EUR @ 1.08 USD
  Assets:Checking  -540 USD

Crypto Trading

2024-01-15 * "Buy Bitcoin"
  Assets:Crypto:BTC  0.5 BTC @ 42000 USD
  Assets:Checking   -21000 USD

2024-06-15 * "Sell Bitcoin"
  Assets:Crypto:BTC  -0.5 BTC {42000 USD} @ 65000 USD
  Assets:Checking    32500 USD
  Income:CapitalGains:Crypto

Multi-Currency Portfolio

2024-01-15 * "International purchase"
  Assets:Brokerage:EU  100 BMW.DE {85.50 EUR}
  Assets:Cash:EUR     -8550 EUR @ 1.09 USD
  ; BMW cost: 8550 EUR
  ; EUR weight: 8550 × 1.09 = 9319.50 USD equivalent

Price in Balance Assertions

Balance assertions don't use prices—they check units:

; Checks that you have 100 EUR, regardless of USD value
2024-01-15 balance Assets:EUR  100 EUR

; To check USD equivalent, use reporting tools, not balance

Validation

Price annotations have minimal validation:

• Amount must be valid
• Currency must be valid

The price value itself is not validated against market data.

Implementation Notes

1. Parse @ as per-unit, @@ as total
2. Compute weight based on presence of cost
3. Optionally generate implicit price entries
4. Store price for market value calculations
5. Price doesn't create or modify lots