SQL Server 2022

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CREATE TABLE raw_data
(
    SerialNum INT
    , PlanID NVARCHAR(10)
    , EEID NVARCHAR(15)
    , Ticker NVARCHAR(10)
    , MarketValue MONEY
    , TotalBalance MONEY
    , CurrentDenominator MONEY
    , AllocationAmount DECIMAL(18,6)
)

INSERT INTO raw_data VALUES
(1, '10241299',    '70973',    'VEMAX',    5654.12,    241781.86,  241781.86,  1),
(2, '10241299',    '70973',    'VMGMX',    5972.14,    241781.86,  236127.74,  1),
(3, '10241299',    '70973',    'VTMGX',    35099.02,   241781.86,  230155.6,   1),
(4, '10241299',    '70973',    'VTSAX',    45529.07,   241781.86,  195056.58,  1),
(5, '10241299',    '70973',    'VFIAX',    149527.51,  241781.86,  149527.51,  1)
;

-- SELECT * FROM raw_data

WITH dataset AS (
  SELECT
    *
    , ROUND(1.0 * MarketValue / CurrentDenominator, 4) AS IncrementedSourceRatio
  FROM
    raw_data
)
  
, recursive AS (
  SELECT
    SerialNum, PlanID, EEID, Ticker, MarketValue, TotalBalance, CurrentDenominator, AllocationAmount
    , IncrementedSourceRatio
    , CAST(0 AS FLOAT) AS AdjustedAllocationCumSum
    , CAST(IncrementedSourceRatio * AllocationAmount AS FLOAT) AS AdjustedAllocation
  FROM
    dataset
  WHERE
    SerialNum = 1

UNION ALL

SELECT
    D.SerialNum, D.PlanID, D.EEID, D.Ticker, D.MarketValue, D.TotalBalance, D.CurrentDenominator, D.AllocationAmount
    , D.IncrementedSourceRatio
    , CAST(R.AdjustedAllocationCumSum + R.AdjustedAllocation AS FLOAT) AS AdjustedAllocationCumSum
    , CAST(D.IncrementedSourceRatio * (D.AllocationAmount - (R.AdjustedAllocationCumSum + R.AdjustedAllocation)) AS FLOAT) AS AdjustedAllocation
  FROM
    recursive AS R
  INNER JOIN
    dataset AS D ON (
      R.SerialNum = D.SerialNum - 1
    )
)
SELECT
  SerialNum, PlanID, EEID, Ticker, MarketValue, TotalBalance, CurrentDenominator
  , AllocationAmount
  , IncrementedSourceRatio
  -- , AdjustedAllocationCumSum
  , AdjustedAllocation
FROM recursive

SerialNum	PlanID	EEID	Ticker	MarketValue	TotalBalance	CurrentDenominator	AllocationAmount	IncrementedSourceRatio	AdjustedAllocation
1	10241299	70973	VEMAX	5654.1200	241781.8600	241781.8600	1.000000	0.02340000000000000	0.0234
2	10241299	70973	VMGMX	5972.1400	241781.8600	236127.7400	1.000000	0.02530000000000000	0.02470798
3	10241299	70973	VTMGX	35099.0200	241781.8600	230155.6000	1.000000	0.15250000000000000	0.14516353305
4	10241299	70973	VTSAX	45529.0700	241781.8600	195056.5800	1.000000	0.23340000000000000	0.18829042885413
5	10241299	70973	VFIAX	149527.5100	241781.8600	149527.5100	1.000000	1.00000000000000000	0.61843805809587