diff --git a/rollforward.sql b/rollforward.sql
new file mode 100644
index 0000000..eedf81d
--- /dev/null
+++ b/rollforward.sql
@@ -0,0 +1,85 @@
+WITH
+--min and max periods
+minmax AS (
+    SELECT
+    (SELECT lower(dur) FROM evt.fspr WHERE id = '2018.08') mind
+    ,(SELECT lower(dur) FROM evt.fspr WHERE id = '2018.11') maxd
+)
+--list each period in min and max
+,prng AS (
+    SELECT 
+        id
+        ,dur
+        ,prop
+    FROM
+        evt.fspr f
+        CROSS JOIN minmax
+    WHERE
+        lower(f.dur) >= mind
+        AND lower(f.dur) <= maxd
+)
+--get every account involved in target range
+,arng AS (
+    SELECT DISTINCT
+        acct
+    FROM
+        evt.bal b
+        INNER JOIN prng ON
+            prng.id = b.fspr
+)
+,bld AS (
+    WITH RECURSIVE rf (acct, id, dur, propr, obal, debits, credits, cbal) AS
+    (
+        SELECT
+            a.acct
+            ,f.id
+            ,f.dur
+            ,f.prop
+            ,COALESCE(b.obal,0)::numeric(12,2)
+            ,COALESCE(b.debits,0)::numeric(12,2)
+            ,COALESCE(b.credits,0)::numeric(12,2)
+            ,COALESCE(b.cbal,0)::numeric(12,2)
+        FROM
+            arng a
+            INNER JOIN evt.fspr f ON
+                lower(f.dur) = (SELECT mind FROM minmax)
+            LEFT OUTER JOIN evt.bal b ON
+                b.acct = a.acct
+                AND b.fspr = f.id
+        
+        UNION ALL
+
+        SELECT
+            rf.acct
+            ,f.id
+            ,f.dur
+            ,f.prop
+            ,rf.cbal
+            ,COALESCE(b.debits,0)::numeric(12,2)
+            ,COALESCE(b.credits,0)::numeric(12,2)
+            ,(rf.cbal + COALESCE(b.debits,0) + COALESCE(b.credits,0))::NUMERIC(12,2)
+        FROM
+            rf
+            INNER JOIN evt.fspr f ON
+                lower(f.dur) = upper(rf.dur)
+            LEFT OUTER JOIN evt.bal b ON
+                b.acct = rf.acct
+                AND b.fspr = f.id
+        WHERE
+            lower(f.dur) <= (SELECT maxd FROM minmax)
+    ) 
+    select * from rf
+)
+SELECT
+    acct
+    ,id
+    ,dur
+    ,obal
+    ,debits
+    ,credits
+    ,cbal
+FROM 
+    bld 
+ORDER BY 
+    acct
+    ,id
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