Understanding participation types and elections for corporate actions

Each corporate action event has at least one participation type, which in turn determines election types and cardinality.

The issuer of your corporate action should provide a specification that determines participation, which you can map to a LUSID participation type as follows:

Mandatory, which means there is only ever one election (that is, there is no choice). You must participate and you must choose that election.
MandatoryWithChoices, which means there can be one or many elections. You must participate and choose one of the elections.
Voluntary, which means there can be one or many elections. You do not have to participate, but if you do you must choose one of the elections.

To discover the participation type(s) and elective choices (if any) for a particular event, call the GetTransactionTemplateSpecification API, for example for CashDividendEvent:

{
  "instrumentEventType": "CashDividendEvent",
  "supportedInstrumentTypes": [
    "Equity",
    "SimpleInstrument"
  ],
  "supportedParticipationTypes": [
    "Mandatory",
    "MandatoryWithChoices"
  ],
  "supportedElectionTypes": [
    {
      "electionType": "CashElection",
      "cardinality": {
        "WhenMandatory": "One",
        "WhenMandatoryWithChoices": "Many"
      },
      "referencedAs": [
        "CashDividendEvent.declaredElection",
        "CashDividendEvent.chosenElection"
      ]
    }
  ],
  ...
}

Note the following for CashDividendEvent:

Two participation types are available: Mandatory and MandatoryWithChoices.
One election type is available, CashElection. If you are required to specify:
- Mandatory, you must specify one currency election and then choose it.
- MandatoryWithChoices, you can specify multiple different currency elections and then choose one of them. Note you can subsequently override this choice on a per-portfolio basis by loading an event instruction.

Most corporate action events have a single participation type. The following have more than one:

Corporate action event	Available participation types	Available election types (and cardinality)	Specify this participation type if…
`BonusIssueEvent`	`Mandatory`	`SecurityOfferElection` (`One`)	There is one security election and you must choose it.
`BonusIssueEvent`	`MandatoryWithChoices`	`SecurityOfferElection` (`One`) `CashOfferElection` (`One`) `LapseElection` (`One`)	There is one security election and/or one cash election and/or one lapse election, and you must choose one.
`CapitalDistributionEvent`	`Mandatory`	`CashElection` (`One`)	There is one currency election and you must choose it.
`CapitalDistributionEvent`	`MandatoryWithChoices`	`CashElection` (`Many`)	There are multiple currency elections and you must choose one.
`CashDividendEvent`	`Mandatory`	`CashElection` (`One`)	There is one currency election and you must choose it.
`CashDividendEvent`	`MandatoryWithChoices`	`CashElection` (`Many`)	There are multiple curency elections and you must choose one.
`MergerEvent`	`Mandatory`	`SecurityOfferElection` (`One`) `CashAndSecurityOfferElection` (`One`)	There is either one security election or one cash & security election, and you must choose the one on offer.
`MergerEvent`	`MandatoryWithChoices`	`SecurityOfferElection` (`One`) `CashAndSecurityOfferElection` (`One`) `CashOfferElection` (`One`)	There is one security election and/or one security & cash election and/or one cash election, and you must choose one.
`TenderEvent`	`Mandatory`	`SecurityOfferElection` (`One`) `CashAndSecurityOfferElection` (`One`) `CashOfferElection` (`One`)	There is either one security election or one cash & security election or one cash election, and you must choose the one on offer.
`TenderEvent`	`Voluntary`	`SecurityOfferElection` (`One`) `CashAndSecurityOfferElection` (`One`) `CashOfferElection` (`One`)	There is either one security election or one cash & security election or one cash election, and you can take one or leave the lot.