Count each person's ISAs in their own benefit unit's capital

changelog.d/2729.fixed.md

@@ -0,0 +1 @@
+The model now counts each person's cash ISA and stocks and shares ISA balances in their own benefit unit for Universal Credit, Housing Benefit, Pension Credit, Income Support, income-based JSA and income-related ESA, so a lodger's or an adult child's ISA no longer adds to the main family's capital.

docs/book/assumptions/isa-inputs-and-capital-flows.md

@@ -107,9 +107,33 @@ respectively, including years after the dataset projection ends, unless the
 dataset holds the person balances for a later year than the total, or a reform
 changes what the total sums or stops a person balance reading its inputs. A
 household input in a situation applies only to its own year; the person
-balances carry the variable-level uprating to later years. The means tests read
-the household totals, so they pool a person's balance with the household's
-other financial capital rather than attribute it to their own benefit unit.
+balances carry the variable-level uprating to later years.
+
+Each means-test formula counts the claimant's and partner's cash and stocks and
+shares ISA balances in their own benefit unit, through
+`cash_isa_countable_capital` and `stocks_and_shares_isa_countable_capital` in
+its `person_sources`, and excludes a dependant's balance, a child's junior ISA
+among them. The formulas subtract a household's counted balances from `cash_isa`
+and `share_like_capital` before they allocate the remainder between benefit
+units. Where the balances sum to less than the total the model holds for the
+year, the remainder stays in the pool. Where their stored sum exceeds the total,
+the model scales them to sum to the total exactly: it rounds each proportional
+share down to a whole step of the total's float32 spacing and gives the steps
+left over, one each, to the members whose shares lost most in rounding. The pool
+then keeps nothing of that total; for totals under £268 million, each holding
+passes a capital limit only where its proportional share does; and a sole holder
+whose balance reaches the total counts exactly the total. For stocks and shares
+ISAs the model takes the smaller of `stocks_and_shares_isa` and
+`share_like_capital` as the total. Data that store only household totals hold no
+balances, so the pool keeps the whole total. The formulas count a balance only
+while the programme's `sources` lists the household source that includes it, so
+a reform that drops `cash_isa` or `share_like_capital` from `sources` drops the
+balances with it. For a Universal Credit unit that reports its capital
+(`benunit_reported_capital` or `uc_reported_capital`, zero or more), the formula
+leaves the unit's claimant's and partner's ISAs in the pool and subtracts the
+report, as it does for their company holdings. A nonnegative
+`pension_credit_reported_capital` replaces the unit's calculated Pension Credit
+capital.
 
 Ordinary accessible cash ISA balances enter the capital sources for Universal
 Credit, Housing Benefit, Pension Credit, Income Support, income-based JSA and

policyengine_uk/parameters/gov/dwp/ESA/income/capital/person_sources.yaml

@@ -1,14 +1,26 @@
 description: >
   Person-level model variables counted as income-related Employment and
-  Support Allowance capital of the person's own benefit unit. They are summed
-  over the benefit unit's claimant and partner (`is_claimant_or_partner`), so
-  they need none of the household proxy that the household `sources` use, and
-  a dependant's holding is left out: regulation 83 adds only the partner's
-  capital to the claimant's. `lifetime_isa_countable_capital` is a Lifetime
-  ISA at its surrender value: regulation 113 values capital at its current
-  market or surrender value, and DMG 52665 counts a Lifetime ISA at 75% of its
-  value under 60 and in full from 60. Lifetime ISAs exist from 6 April 2017,
-  and the list is empty before then.
+  Support Allowance capital of the person's own benefit unit. The formulas sum
+  these sources over the benefit unit's claimant and partner
+  (`is_claimant_or_partner`) and exclude dependants: DWP excludes children's
+  capital under regulation 83(2). `lifetime_isa_countable_capital` values a
+  Lifetime ISA at its surrender value: DWP values capital at its current
+  market or surrender value under regulation 113, and DMG 52665 counts a
+  Lifetime ISA at 75% of its value under 60 and in full from 60. Lifetime ISAs
+  exist from 6 April 2017, and the formulas count them from then.
+  `cash_isa_countable_capital` and `stocks_and_shares_isa_countable_capital`
+  hold a member's cash and stocks and shares ISA balances, bounded by the
+  household total. The account investor beneficially owns an ordinary ISA's
+  investments, and the named child owns a junior ISA's investments (Individual
+  Savings Account Regulations 1998 reg. 4(6)(a) and reg. 2B(c)). The formulas
+  subtract each bounded ISA balance from its household source (`cash_isa`,
+  `share_like_capital`) and count it in the holder's unit. When a household's
+  balances exceed its total, the model scales them to sum to the total
+  exactly, rounding each share down or up to a whole float32 step of the
+  total. When a reform removes a household source from `sources`, the formulas
+  exclude the corresponding ISA person source. With household totals alone,
+  the formulas leave the whole total in the pool. The ISA Regulations came
+  into force for all other purposes on 6 April 1999 (reg. 1).
 metadata:
   label: Income-related ESA person-level capital sources
   period: year
@@ -20,7 +32,15 @@ metadata:
       href: https://www.legislation.gov.uk/uksi/2008/794/regulation/113
     - title: Decision Makers' Guide, Chapter 52 (Capital), para. 52665
       href: https://assets.publishing.service.gov.uk/media/69d8f30ad3e08b8871b665ac/dmg-Ch-52.pdf
+    - title: The Individual Savings Account Regulations 1998 reg. 4
+      href: https://www.legislation.gov.uk/uksi/1998/1870/regulation/4
+    - title: The Individual Savings Account Regulations 1998 reg. 2B
+      href: https://www.legislation.gov.uk/uksi/1998/1870/regulation/2B
 values:
-  2008-10-27: []
+  2008-10-27:
+    - cash_isa_countable_capital
+    - stocks_and_shares_isa_countable_capital
   2017-04-06:
     - lifetime_isa_countable_capital
+    - cash_isa_countable_capital
+    - stocks_and_shares_isa_countable_capital

policyengine_uk/parameters/gov/dwp/ESA/income/capital/sources.yaml

@@ -1,6 +1,10 @@
 description: >
-  Ordinary cash ISA balances are separate from savings and are included at
-  their accessible cash value, without a generic cash sale-cost deduction.
+  The formulas count ordinary accessible cash ISAs separately from savings,
+  at their cash value, without a generic cash sale-cost deduction.
+  Where the data tie a cash ISA or stocks and shares ISA balance to a member,
+  the formulas count it through `person_sources` in the holder's own benefit
+  unit and subtract it from `cash_isa` or `share_like_capital` before they
+  allocate the rest.
   Model variables currently mapped to countable income-related Employment and
   Support Allowance capital. The Employment and Support Allowance Regulations
   2008 treat capital as assessable unless it is disregarded under Schedule 9.
@@ -19,11 +23,11 @@ description: >
   occupational or personal pension and the value of funds held under a
   personal pension scheme. Other Schedule 9 disregards and the higher
   residential-care capital disregard are not yet modeled because the current
-  dataset does not isolate those states or asset holdings. Because the dataset
-  only provides household-level capital stocks, the model allocates the full
-  household total to benunits with a reported income-related ESA award and
-  only falls back to an adult-share proxy when nobody in the household is on
-  that reported claim path. That allocation is a data approximation, not a
+  dataset does not isolate those states or asset holdings. For capital whose
+  owner the data do not identify, the model allocates the full household
+  remainder to benunits with a reported income-related ESA award and falls
+  back to claimant and partner shares when nobody in the household reports
+  such an award. That allocation is a data approximation, not a
   legislated ownership rule.
 metadata:
   label: Income-related ESA countable capital sources

policyengine_uk/parameters/gov/dwp/JSA/income/capital/person_sources.yaml

@@ -1,15 +1,27 @@
 description: >
   Person-level model variables counted as income-based Jobseeker's Allowance
-  capital of the person's own benefit unit. They are summed over the benefit
-  unit's claimant and partner (`is_claimant_or_partner`), so they need none of
-  the household proxy that the household `sources` use, and a dependant's
-  holding is left out: regulation 109 kept a child's or young person's capital
-  out of the claimant's, and since children moved to child tax credit they are
-  outside the assessment altogether. `lifetime_isa_countable_capital` is a
-  Lifetime ISA at its surrender value: regulation 111 values capital at its
-  current market or surrender value, and DMG 29665 counts a Lifetime ISA at
-  75% of its value under 60 and in full from 60. Lifetime ISAs exist from 6
-  April 2017, and the list is empty before then.
+  capital of the person's own benefit unit. The formulas sum these sources
+  over the benefit unit's claimant and partner (`is_claimant_or_partner`) and
+  exclude dependants: DWP excludes children's capital under regulation 109
+  until SI 2003/455 applies, and regulation 88(2) from then.
+  `lifetime_isa_countable_capital` values a Lifetime ISA at its surrender
+  value: DWP values capital at its current market or surrender value under
+  regulation 111, and DMG 29665 counts a Lifetime ISA at 75% of its value
+  under 60 and in full from 60. Lifetime ISAs exist from 6 April 2017, and the
+  formulas count them from then. `cash_isa_countable_capital` and
+  `stocks_and_shares_isa_countable_capital` hold a member's cash and stocks
+  and shares ISA balances, bounded by the household total. The account
+  investor beneficially owns an ordinary ISA's investments, and the named
+  child owns a junior ISA's investments (Individual Savings Account
+  Regulations 1998 reg. 4(6)(a) and reg. 2B(c)). The formulas subtract each
+  bounded ISA balance from its household source (`cash_isa`,
+  `share_like_capital`) and count it in the holder's unit. When a household's
+  balances exceed its total, the model scales them to sum to the total
+  exactly, rounding each share down or up to a whole float32 step of the
+  total. When a reform removes a household source from `sources`, the formulas
+  exclude the corresponding ISA person source. With household totals alone,
+  the formulas leave the whole total in the pool. The ISA Regulations came
+  into force for all other purposes on 6 April 1999 (reg. 1).
 metadata:
   label: Income-based JSA person-level capital sources
   period: year
@@ -21,7 +33,16 @@ metadata:
       href: https://www.legislation.gov.uk/uksi/1996/207/regulation/111
     - title: Decision Makers' Guide, Chapter 29 (Capital), para. 29665
       href: https://assets.publishing.service.gov.uk/media/6894a69d3080e72710b2e237/dmg-ch-29.pdf
+    - title: The Individual Savings Account Regulations 1998 reg. 4
+      href: https://www.legislation.gov.uk/uksi/1998/1870/regulation/4
+    - title: The Individual Savings Account Regulations 1998 reg. 2B
+      href: https://www.legislation.gov.uk/uksi/1998/1870/regulation/2B
 values:
   1996-10-07: []
+  1999-04-06:
+    - cash_isa_countable_capital
+    - stocks_and_shares_isa_countable_capital
   2017-04-06:
     - lifetime_isa_countable_capital
+    - cash_isa_countable_capital
+    - stocks_and_shares_isa_countable_capital

policyengine_uk/parameters/gov/dwp/JSA/income/capital/sources.yaml

@@ -1,6 +1,10 @@
 description: >
-  Ordinary cash ISA balances are separate from savings and are included at
-  their accessible cash value, without a generic cash sale-cost deduction.
+  The formulas count ordinary accessible cash ISAs separately from savings,
+  at their cash value, without a generic cash sale-cost deduction.
+  Where the data tie a cash ISA or stocks and shares ISA balance to a member,
+  the formulas count it through `person_sources` in the holder's own benefit
+  unit and subtract it from `cash_isa` or `share_like_capital` before they
+  allocate the rest.
   Model variables currently mapped to countable income-based Jobseeker's
   Allowance capital. The Jobseeker's Allowance Regulations 1996 treat capital
   as assessable unless it is disregarded under Schedule 8. The current
@@ -20,10 +24,10 @@ description: >
   personal pension scheme. Other Schedule 8 disregards, the higher
   residential-care capital disregard, and the separate child-capital disregard
   are not yet modeled because the current dataset does not isolate those
-  states or asset holdings. Because the dataset only provides household-level
-  capital stocks, the model allocates the full household total to benunits
-  with a reported income-based JSA award and only falls back to an adult-share
-  proxy when nobody in the household is on that reported claim path. That
+  states or asset holdings. For capital whose owner the data do not identify,
+  the model allocates the full household remainder to benunits with a
+  reported income-based JSA award and falls back to claimant and partner
+  shares when nobody in the household reports such an award. That
   allocation is a data approximation, not a legislated ownership rule.
 metadata:
   label: Income-based JSA countable capital sources

policyengine_uk/parameters/gov/dwp/housing_benefit/means_test/capital/person_sources.yaml

@@ -1,15 +1,32 @@
 description: >
   Person-level model variables counted as Housing Benefit capital of the
-  person's own benefit unit. They are summed over the benefit unit's claimant
-  and partner (`is_claimant_or_partner`), so they need none of the household
-  proxy that the household `sources` use, and a dependant's holding is left
-  out: regulation 45 says the capital of a child or young person in the
-  claimant's family is not the claimant's. `lifetime_isa_countable_capital` is
-  a Lifetime ISA at its surrender value: regulation 47 (regulation 45 of the
-  pension-age regulations) values capital at its current market or surrender
-  value, in the words of the DWP benefits' regulations, for which DWP guidance
-  counts a Lifetime ISA at 75% of its value under 60 and in full from 60.
-  Lifetime ISAs exist from 6 April 2017, and the list is empty before then.
+  person's own benefit unit. The formulas sum these sources over the benefit
+  unit's claimant and partner (`is_claimant_or_partner`) and exclude
+  dependants: local authorities exclude children's capital under regulation
+  45 (regulation 23(3) of the pension-age regulations).
+  `lifetime_isa_countable_capital` values a Lifetime ISA at its surrender
+  value: local authorities value capital at its current market or surrender
+  value under regulation 47 (regulation 45 of the pension-age regulations),
+  whose words match the DWP benefits' valuation rules, and DWP guidance on
+  those rules counts a Lifetime ISA at 75% of its value under 60 and in full
+  from 60. Lifetime ISAs exist from 6 April 2017, and the formulas count them
+  from then. `cash_isa_countable_capital` and
+  `stocks_and_shares_isa_countable_capital` hold a member's cash and stocks
+  and shares ISA balances, bounded by the household total. The account
+  investor beneficially owns an ordinary ISA's investments, and the named
+  child owns a junior ISA's investments (Individual Savings Account
+  Regulations 1998 reg. 4(6)(a) and reg. 2B(c)). In the ordinary calculation,
+  the formula subtracts each bounded ISA balance from its household source
+  (`cash_isa`, `share_like_capital`) and counts it in the holder's unit. For a
+  family on a passporting benefit, or at pension age on a guarantee credit,
+  the formula returns zero capital, and for a savings-credit-only award it
+  uses the Pension Credit capital assessment. When a household's balances
+  exceed its total, the model scales them to sum to the total exactly,
+  rounding each share down or up to a whole float32 step of the total. When a
+  reform removes a household source from `sources`, the formulas exclude the
+  corresponding ISA person source. With household totals alone, the formulas
+  leave the whole total in the pool. The ISA Regulations came into force for
+  all other purposes on 6 April 1999 (reg. 1).
 metadata:
   label: Housing Benefit person-level capital sources
   period: year
@@ -23,7 +40,15 @@ metadata:
       href: https://www.legislation.gov.uk/uksi/2006/214/regulation/45
     - title: Decision Makers' Guide, Chapter 29 (Capital), para. 29665 (Income Support and JSA, whose valuation rule has the same words)
       href: https://assets.publishing.service.gov.uk/media/6894a69d3080e72710b2e237/dmg-ch-29.pdf
+    - title: The Individual Savings Account Regulations 1998 reg. 4
+      href: https://www.legislation.gov.uk/uksi/1998/1870/regulation/4
+    - title: The Individual Savings Account Regulations 1998 reg. 2B
+      href: https://www.legislation.gov.uk/uksi/1998/1870/regulation/2B
 values:
-  2006-04-10: []
+  2006-04-10:
+    - cash_isa_countable_capital
+    - stocks_and_shares_isa_countable_capital
   2017-04-06:
     - lifetime_isa_countable_capital
+    - cash_isa_countable_capital
+    - stocks_and_shares_isa_countable_capital

policyengine_uk/parameters/gov/dwp/housing_benefit/means_test/capital/sources.yaml

@@ -1,6 +1,10 @@
 description: >
-  Ordinary cash ISA balances are separate from savings and are included at
-  their accessible cash value, without a generic cash sale-cost deduction.
+  The formulas count ordinary accessible cash ISAs separately from savings,
+  at their cash value, without a generic cash sale-cost deduction.
+  Where the data tie a cash ISA or stocks and shares ISA balance to a member,
+  the formulas count it through `person_sources` in the holder's own benefit
+  unit and subtract it from `cash_isa` or `share_like_capital` before they
+  allocate the rest.
   Model variables currently mapped to countable Housing Benefit capital. The
   Housing Benefit Regulations 2006 treat the whole of a claimant's capital as
   assessable unless it is disregarded under Schedule 6. The current mappings
@@ -22,8 +26,8 @@ description: >
   regulations make the same disregard). Datasets built before private pension
   wealth was split out of `corporate_wealth` still carry it inside
   `share_like_capital`. Other Schedule 6 disregards within these broad asset
-  classes are not yet split out separately. Because the dataset only provides
-  household-level capital stocks, the model allocates them across benunits
+  classes are not yet split out separately. For capital whose owner the data
+  do not identify, the model allocates the household remainder across benunits
   using an adult-share proxy.
 metadata:
   label: Housing Benefit countable capital sources