diff --git a/README.md b/README.md
index 9db89b0..b805b11 100644
--- a/README.md
+++ b/README.md
@@ -43,6 +43,7 @@ TSM price strings can reference built-in data sources and combine them with math
 ### Accounting sources
 - `avgSell`: Average sell price.
 - `avgBuy`: Average buy price.
+- `smartAvgBuy`: Smart average buy price (uses current holdings to weight recent buys).
 - `maxSell`: Maximum sell price.
 - `maxBuy`: Maximum buy price.
 - `minSell`: Minimum sell price.