Evaluation

Evaluation converts the AST into a sequence of vesting installments that are either resolved (with a concrete ISO date), unresolved (with a symbolic date and blockers), or impossible (with blockers).

The evaluator:

Attempts to resolve a vesting start date
Builds the periodic dates (or symbolic dates) for the vesting period
Treats the grant date as a "soft cliff" if any vesting installments precede the grant date (see below)
Applies any explicit CLIFF if present (including partial knowledge for LATER OF cliffs, see below)
Allocates the statement's amount across installments using the configured allocation mode
Emits vesting installments with metadata.

note

The shape and content of all metadata described below should be viewed as a bogey intended for discussion. All comments welcome!

Evaluation context

The following evaluation context is supplied the evaluator:

{
  events: { grantDate: OCTDate } & Record<string, OCTDate | undefined>,
  grantQuantity: number,
  asOf: OCTDate,
  vesting_day_of_month: vesting_day_of_month
  allocation_type: allocation_type
}

Events

The grant date of the security (events[grantDate]) and the quantity of shares (grantQuantity) are required.

If the vesting start is resolved through the course of the evaluation, EVENT vestingStart is added to the events record.

Vesting Day of Month

vesting_day_of_month tracks the OCT schema found here, and defaults to VESTING_START_DAY_OR_LAST_DAY_OF_MONTH.

Allocation Type

allocation_type tracks the OCT schema found here, and defaults to CUMULATIVE_ROUND_DOWN.

As Of Date

The asOf date is used to determine whether time-limited conditions have occured, and defaults to the current date if not provided.

For instance, consider a vesting schedule that starts if a milestone occurs before a given date in the future:

VEST FROM EVENT milestone BEFORE DATE 9999-01-01

If this statement is evaluated with an unresolved EVENT milestone, then vesting start will be unresolved. The returned tranche will be UNRERESOLVED rather than IMPOSSIBLE because the milestone event may occur in the future and the deadline has not yet elapsed.

Resolved Schedule

A schedule of resolved installments has the folllowing shape:

{
  installments: {
    amount: number,
    date: OCTDate,
    meta: {
      state: "RESOLVED"
    }
  },
  blockers: [] // empty array when installments are resolved
}

Example: Standard Time-Based Vesting

A time-based vesting schedule without conditions always resolves. The example below assumes a grant date of 2025-01-01.

DSL

100 VEST
  OVER 48 months EVERY 12 months

Vesting Installments

Amount	Date	State
25	2026-01-01	RESOLVED
25	2027-01-01	RESOLVED
25	2028-01-01	RESOLVED
25	2029-01-01	RESOLVED

Unresolved Schedule

A schedule of unrsolved installments has the following shape:

{
  installments: {
    amount: number,
    meta: {
      state: "UNRESOLVED",
      date: SymbolicDate,
      unresolved: string[] // the unresolved portion of the DSL statement
    }
  },
  blockers: Blocker[]
}

Blockers

Unresolved installments include one of the following blockers:

type UnresolvedBlocker =
  | {
      type: "EVENT_NOT_YET_OCCURRED";
      event: string;
    }
  | {
      type: "UNRESOLVED_SELECTOR";
      selector: "EARLIER_OF" | "LATER_OF";
      blockers: Blocker[];
    }
  | {
      type: "DATE_NOT_YET_OCCURRED";
      date: OCTDate;
    }
  | {
      type: "UNRESOLVED_CONDITION";
      condition: Omit<VestingNode, "type">;
    };

Symbolic Dates

Unresolved installments contain the one of the following symbolic dates:

Before Vesting Date

{
  type: "UNRESOLVED_VESTING_START";
}

DSL

100 VEST FROM EVENT milestone

Vesting Installments

Installments

Amount	Date	Status	Unresolved
100	`{type: UNRESOLVED_VESTING_START }`	UNRESOLVED	`EVENT milestone`

Blockers

{
  "type": "EVENT_NOT_YET_OCCURRED",
  "event": "milestone"
}

Start Plus

{
  type: "START_PLUS",
  unit: "DAYS" | "MONTHS",
  steps: number
}

DSL

100 VEST FROM LATER OF(
  DATE 2025-01-01,
  EVENT milestone2
)
  OVER 48 months EVERY 12 months

Vesting Installments

Installments

Amount	Date	State	Unresolved
25	`{ type: START_PLUS, unit: MONTHS, steps: 0 }`	UNRESOLVED	`EVENT milestone2`
25	`{ type: START_PLUS, unit: MONTHS, steps: 12 }`	UNRESOLVED	`EVENT milestone2`
25	`{ type: START_PLUS, unit: MONTHS, steps: 24 }`	UNRESOLVED	`EVENT milestone2`
25	`{ type: START_PLUS, unit: MONTHS, steps: 36 }`	UNRESOLVED	`EVENT milestone2`

Blockers

{
  "type": "EVENT_NOT_YET_OCCURRED",
  "event": "milestone2"
}

Maybe Before Cliff

{
  type: "UNRESOLVED_CLIFF",
  date: OCTDate
}

DSL

100 VEST
  OVER 48 months EVERY 12 months
  CLIFF EVENT milestone

Vesting Installments

Installments

Amount	Date	State	Unresolved
25	`{ type: UNRESOLVED_CLIFF, date: 2026-01-01 }`	UNRESOLVED	`EVENT milestone`
25	`{ type: UNRESOLVED_CLIFF, date: 2027-01-01 }`	UNRESOLVED	`EVENT milestone`
25	`{ type: UNRESOLVED_CLIFF, date: 2028-01-01 }`	UNRESOLVED	`EVENT milestone`
25	`{ type: UNRESOLVED_CLIFF, date: 2029-01-01 }`	UNRESOLVED	`EVENT milestone`

Blockers

{
  "type": "EVENT_NOT_YET_OCCURRED",
  "event": "milestone"
}

Impossible Installments

Impossible installments have the following shape:

{
  amount: number,
  meta: {
    state: "IMPOSSIBLE",
    blockers: string[] // the impossible portion of the DSL statement
  }
}

Blockers

Impossible installments include one of the following blockers:

type ImpossibleBlocker =
  | {
      type: "IMPOSSIBLE_SELECTOR";
      selector: "EARLIER_OF" | "LATER_OF";
      blockers: ImpossibleBlocker[];
    }
  | {
      type: "IMPOSSIBLE_CONDITION";
      condition: Omit<VestingNode, "type">;
    };

DSL

100 VEST FROM EVENT milestone BEFORE DATE 2025-01-01

Vesting Installments

Installments

Amount	State	Unresolved
100	IMPOSSIBLE	`EVENT milestone BEFORE DATE 2025-01-01`

Blockers

{
  "type": "IMPOSSIBLE_CONDITION",
  "condition": {
    "base": {
      "type": "EVENT",
      "value": "milestone"
    },
    "offsets": [],
    "constraints": {
      "type": "ATOM",
      "constraint": {
        "type": "BEFORE",
        "base": {
          "type": "SINGLETON",
          "base": {
            "type": "DATE",
            "value": "2025-01-01"
          },
          "offsets": []
        },
        "strict": false
      }
    }
  }
}

Special Cases

Partial Knowledge for LATER OF selectors

In the case of a LATER OF selector, if some but not all items are resolved, we preserve the information gleaned from the resolved items.

By way of example, consider a 4-year quarterly vesting schedule, with a cliff at the later of 12 months from the vesting start and a milestone event. The grant is made on 2025-01-01 over 100 shares.

This vesting schedule is described with the following statement:

100 VEST
  OVER 48 months EVERY 3 months
  CLIFF LATER OF(
    +12 months,
    EVENT milestone
  )

If this statement is evaluated at a time when EVENT milestone is not resolved, the vesting start will be unresolved.

Nonetheless, since this is a LATER OF statement we know that a that a 12 month cliff will always apply:

Amount	Symbolic Date	State	Unresolved
25	`{type: UNRESOLVED_CLIFF, date: 2026-01-01}`	UNRESOLVED	EVENT milestone
6	`{type: UNRESOLVED_CLIFF, date: 2026-04-01}`	UNRESOLVED	EVENT milestone
6	`{type: UNRESOLVED_CLIFF, date: 2026-07-01}`	UNRESOLVED	EVENT milestone
6	`{type: UNRESOLVED_CLIFF, date: 2026-10-01}`	UNRESOLVED	EVENT milestone
7	`{type: UNRESOLVED_CLIFF, date: 2027-01-01}`	UNRESOLVED	EVENT milestone
6	`{type: UNRESOLVED_CLIFF, date: 2027-04-01}`	UNRESOLVED	EVENT milestone
6	`{type: UNRESOLVED_CLIFF, date: 2027-07-01}`	UNRESOLVED	EVENT milestone
6	`{type: UNRESOLVED_CLIFF, date: 2027-10-01}`	UNRESOLVED	EVENT milestone
7	`{type: UNRESOLVED_CLIFF, date: 2028-01-01}`	UNRESOLVED	EVENT milestone
6	`{type: UNRESOLVED_CLIFF, date: 2028-04-01}`	UNRESOLVED	EVENT milestone
6	`{type: UNRESOLVED_CLIFF, date: 2028-07-01}`	UNRESOLVED	EVENT milestone
6	`{type: UNRESOLVED_CLIFF, date: 2028-10-01}`	UNRESOLVED	EVENT milestone
7	`{type: UNRESOLVED_CLIFF, date: 2029-01-01}`	UNRESOLVED	EVENT milestone

Vesting start before grant date

Awards are often granted with a vesting start that precedes the grant date in order to provide vesting credit for services that have already been provided. In these situations the evaluator accrues vesting amounts until the grant date.

For instance, consider an award over 100 shares granted on 2025-01-01 with a 4-year quarterly vesting schedule commencing on 2024-01-01. All four vesting installments in calendar year 2024 are accrued and vest on the grant date.

100 VEST FROM DATE 2024-01-01
  OVER 48 months EVERY 3 months

Amount	Date	State
25	2025-01-01	RESOLVED
6	2025-04-01	RESOLVED
6	2025-07-01	RESOLVED
6	2025-10-01	RESOLVED
7	2026-01-01	RESOLVED
6	2026-04-01	RESOLVED
6	2026-07-01	RESOLVED
6	2026-10-01	RESOLVED
7	2027-01-01	RESOLVED
6	2027-04-01	RESOLVED
6	2027-07-01	RESOLVED
6	2027-10-01	RESOLVED
7	2028-01-01	RESOLVED

Evaluation context​

Events​

Vesting Day of Month​

Allocation Type​

As Of Date​

Resolved Schedule​

Example: Standard Time-Based Vesting​

DSL​

Vesting Installments​

Unresolved Schedule​

Blockers​

Symbolic Dates​

Before Vesting Date​

DSL​

Vesting Installments​

Installments​

Blockers​

Start Plus​

DSL​

Vesting Installments​

Installments​

Blockers​

Maybe Before Cliff​

DSL​

Vesting Installments​

Installments​

Blockers​

Impossible Installments​

Blockers​

DSL​

Vesting Installments​

Installments​

Blockers​

Special Cases​

Partial Knowledge for LATER OF selectors​

Vesting start before grant date​

Evaluation context

Events

Vesting Day of Month

Allocation Type

As Of Date

Resolved Schedule

Example: Standard Time-Based Vesting

DSL

Vesting Installments

Unresolved Schedule

Blockers

Symbolic Dates

Before Vesting Date

DSL

Vesting Installments

Installments

Blockers

Start Plus

DSL

Vesting Installments

Installments

Blockers

Maybe Before Cliff

DSL

Vesting Installments

Installments

Blockers

Impossible Installments

Blockers

DSL

Vesting Installments

Installments

Blockers

Special Cases

Partial Knowledge for LATER OF selectors

Vesting start before grant date