Imported from carta/plugins (plugins/carta-cap-table/skills/carta-valuation-history/SKILL.md). Install upstream with npx skills add carta/plugins --skill carta-valuation-history. Copyright stays with the author.

Valuation History

Fetch a company's fair market value (FMV) history.

FMV is not always a 409A. A 409A is the US instrument; a UK company is valued under an EMI or CSOP agreement with HMRC, and other companies use a share-price report. Read whichever the company actually has, and never tell a company with a valid EMI valuation that it has none.

When to Use

• "What's our current valuation?" / "What's the current 409A?"
• "Show me the FMV history"
• "When does the valuation expire?"
• "What's the exercise price for common stock?"
• "Has the FMV changed recently?"
• "Is the valuation still valid?"

Prerequisites

You need the corporation_id. Get it from list_accounts if you don't have it.

Data Retrieval

call_tool({"name": "cap_table__get__valuations", "arguments": {"corporation_id": corporation_id}})

Optional valuation_source filters to one or more of EMI, CSOP, 409A, SHARE_PRICE. Omit it — the point of this command is that it covers every source at once.

Response Format

{
  "count": 2,
  "active": [
    {
      "price": "0.500000000000",
      "currency": "GBP",
      "valuation_type": "AMV",
      "support_reference_type": "EMI_VALUATION_REPORT",
      "effective_date": "2026-01-15",
      "expiration_date": "2027-01-14",
      "share_class_name": "Ordinary",
      "status": "ACTIVE"
    }
  ],
  "history": []
}

history holds every row including expired ones; active is the subset the server considers live.

Key Fields

• price: FMV per share, a high-precision decimal string (e.g. "0.500000000000")
• currency: ISO code for this row — read it per row, never assume
• valuation_type: AMV, UMV, FMV, or SHARE_PRICE
• support_reference_type: which instrument the row came from (409A / EMI / CSOP / share price)
• effective_date / expiration_date: ISO YYYY-MM-DD
• status: ACTIVE or EXPIRED, computed server-side
• share_class_name: e.g. "Common", "Ordinary"

AMV and UMV

A single HMRC valuation produces two prices, both live at once:

• AMV — actual market value, discounted for restrictions on the shares
• UMV — unrestricted market value

They are not duplicates and one is not "the real one". Show both, labelled. If asked which applies to a specific grant, say that depends on the grant's terms and point the user to their equity advisor — the data does not record it, and the two carry different tax outcomes.

Fallback

If cap_table__get__valuations is unavailable for the company, fall back to cap_table__get__409a_valuations, which returns {count, current_409a, history} for US 409A data only. That response has no currency field — present its prices unlabelled rather than assuming a symbol, and check current_409a.is_expired before calling it current.

Workflow

Step 1 — Fetch Valuations

call_tool({"name": "cap_table__get__valuations", "arguments": {"corporation_id": corporation_id}})

Step 2 — Identify the Current Valuation

Use active. Do not re-derive live-vs-expired from dates: the server applies per-source rules (a share-price report has its own state; a null expiration means open-ended) that a date comparison gets wrong.

Where you do sort, sort on parsed dates, never raw strings. These are ISO so they happen to sort correctly, but the 409A fallback returns MM/DD/YYYY, where a string sort is month-major and ranks 12/01/2023 above 04/25/2025.

If active holds more than one row, they are all current — an AMV/UMV pair, or several share classes. Present them all rather than picking one.

Step 3 — Check Expiration

• Within 90 days of today — flag as a time-sensitive action item, not just a data point: bold it, give the exact days remaining, and recommend starting renewal now (especially if a financing round is in progress, since closing will likely push past the expiry date).
• Already past — flag as expired.
• No expiration_date — say it does not expire on a fixed date rather than inferring one.

Step 4 — Present Results

Show the history table and trend summary (see Presentation section).

Gates

Required inputs: corporation_id. If missing, call AskUserQuestion before proceeding (see carta-interaction-reference §4.1).

AI computation: No — this skill presents Carta data directly.

Presentation

Format: Table + trend summary

BLUF lead: Lead with the current FMV per share — with its currency and source — and its effective/expiration dates, before showing the history table.

Sort order: By effective_date descending (most recent first).

Date format: MMM d, yyyy (e.g. "Jan 15, 2026").

Currency: format price with the row's own currency, trimming trailing zeros. Never hardcode a $, and never default to USD — a GBP valuation shown as dollars is a reporting error, not a cosmetic one.

Drop the Type and Source columns when every row shares the same values (a US-only company gets back its familiar 409A table).

Do not render a bar chart for FMV history — values in mature companies cluster near the maximum, making bars uninformative (all bars look the same width). The table is sufficient. Instead, after the table, add a one-line trend summary:

FMV has grown Nx since YYYY, with [acceleration/steady growth] since [year].

Only compare like with like. A growth multiple across two different currencies is meaningless, and so is one that mixes an AMV with a UMV. Compute the trend within a single currency and a single valuation_type; if the series spans more than one, give a separate line for each or omit the trend entirely.

If multiple share classes exist, group by share class name in the table.

Caveats

• The price field is a string with many trailing zeros — always parse and format before displaying.
• A valuation with a past expiration_date should never be used for new grant pricing. Flag it prominently.
• Valuations are point-in-time snapshots — a material event (e.g. a new financing round) can invalidate a current valuation before its expiration date.
• This skill reads valuations; it cannot create or update one. Route those requests to the Carta app — for a non-US company that is the international valuations dashboard, not the 409A ledger.