Carta built the category, and for years it was the default choice for good reason. Today, a lot of founders are questioning that default. They’re tired of pricing that punishes growth, an interface that requires insider knowledge to navigate, and a support team that’s hard to reach when something actually matters.
Mantle is one of the more compelling alternatives with flat-rate pricing, unlimited stakeholders, native Canadian support (rare in this space), and a white-glove migration process that most founders say takes less than a week. This guide walks you through exactly how to make the switch, what to watch out for, and how to think about the transition so nothing falls through the cracks.
Before You Begin: What You’ll Need
Before kicking off the migration, gather the following:
- Access to your Carta account with admin permissions
- Your cap table documents: stock purchase agreements, SAFE/convertible notes, any board consents related to equity
- A list of current stakeholders: founders, employees with equity, investors, advisors
- Your company’s certificate/articles of incorporation and any amendments
- Vesting schedules for all outstanding option grants
- Cap table spreadsheet export: If available, this will help streamline the migration process.
Which path are you on?
- Paid plan (Essentials or Growth): Grant Mantle admin access to your Carta account and we’ll handle the migration end-to-end.
- Free plan (Starter): Export your Carta data and use Mantle’s AI assistant (Clerk) to build your cap table yourself.
Path A: Paid Plan (We’ll Handle It for You)
If you’re on Mantle Essentials or Mantle Growth, white-glove onboarding is included. You don’t need to export anything manually or re-enter a single transaction. Here’s how it works.
Step 1: Sign Up for Mantle
Head to withmantle.com and create your account on an Essentials or Growth plan. Once you’re set up, your onboarding contact will reach out to kick off the migration.
Step 2: Add Mantle to Your Carta Account
This is the core step. Adding Mantle as a collaborator on your Carta account lets their team pull your full cap table, transaction history, and associated documents directly.
To do this in Carta:
- Go to Settings → Team
- Invite your Mantle onboarding contact using the email they provide
- Assign them Admin or Legal Admin permissions
- They’ll confirm access and begin the migration
That’s it on your end. From here, Mantle’s team handles the data pull, the document reconciliation, and the cap table build in Mantle.
Step 3: Mantle Builds and Verifies Your Cap Table
Once they have access, Mantle’s team will:
- Import your full transaction history
- Map all security types (common stock, preferred stock, options, SAFEs, convertible notes, warrants)
- Reconstruct vesting schedules for each outstanding grant
- Flag any discrepancies between your Carta data and your underlying legal documents
- Present you with a completed cap table for your review
Most migrations complete within 1–5 business days. If your documents are clean and well-organized, it’s often closer to 1–2 days.
Step 4: Review and Approve Your Cap Table
Before anything goes live, you’ll review the completed Mantle cap table and confirm it matches what you had in Carta. Check:
- Total shares outstanding and authorized shares
- Fully diluted share count (including unissued option pool)
- Each stakeholder’s holdings — share count, share class, and ownership percentage
- Vesting schedules — start dates, cliff dates, total vested and unvested shares per grant
- Option exercise prices — critical for 409A compliance
- SAFE and convertible note terms — valuation caps, discount rates, any side letters
If you work with one, we also recommend having your attorney/paralegal do a quick review before you finalize.
Step 5: Invite Your Stakeholders
Once your cap table is verified, invite your stakeholders to Mantle. All plans include unlimited stakeholders (yes, you read that right). You can invite everyone from co-founders, employees with equity, investors, advisors, and your legal counsel without worrying about being pushed up to a higher pricing tier.
Step 6: Cancel Carta
Once the following are complete, you’re safe to cancel your Carta subscription.
Path B: Free Plan (Self-Serve with AI Tooling)
If you’re on Mantle Starter, you’ll export your data from Carta and use Mantle’s AI features to build your cap table.
Step 1: Export Your Data from Carta
Log into Carta and navigate to your cap table. Go to Cap Table → Reports and download the following:
- Cap table summary — full stakeholder view with share counts, security types, and ownership percentages
- Transaction history — every issuance, cancellation, transfer, and exercise on record
- Option grant details — grant dates, exercise prices, vesting schedules, cliff dates, and expiration dates
- SAFE and convertible note details — principal amounts, discount rates, valuation caps, and any side letters
- Investor contact information — names, emails, and addresses for all stakeholders
Download both CSV and PDF formats. The CSVs are what you’ll work from; the PDFs are your audit trail.
Step 2: Sign Up for Mantle Starter
Head to withmantle.com and create a free Starter account. Mantle Starter is available at no cost, so it’s great for early-stage companies since it still includes all of the core cap table features.
Step 3: Chat with Mantle Clerk
In Mantle, start up a chat with Clerk to help you build out your cap table. Simply let it know what you’re trying to do, and Clerk will walk you through your next steps.
Step 4: Use AI Extract
If you don’t want to use Mantle Clerk, you can use Mantle’s AI extract feature to read your legal documents and auto-populate your cap table for you. Review each entry as it’s generated and correct anything the AI misreads.
Cross-reference the generated cap table against your Carta CSV exports to catch anything that was missed or parsed incorrectly.
Step 5: Verify and Reconcile
Run a side-by-side comparison between your Carta cap table summary and your Mantle cap table. Check:
- Total shares outstanding and authorized shares
- Fully diluted share count (including unissued option pool)
- Each stakeholder’s holdings — share count, share class, and ownership percentage
- Vesting schedules — start dates, cliff dates, total vested and unvested per grant
- Option exercise prices
- SAFE and note conversion terms
When in doubt, your original legal documents are the source of truth. Have your law firm review the completed cap table before you proceed.
Step 6: Invite Your Stakeholders
Once your cap table is verified, invite your stakeholders. Mantle Starter includes unlimited stakeholders, so add co-founders, employees with equity, advisors, investors, and legal counsel.
Step 7: Cancel Carta
Once the following are complete, you’re safe to cancel:
- Your Mantle cap table has been reviewed and approved by your attorney
- All stakeholders have received and accepted their Mantle invites
- You’ve downloaded and archived your Carta data exports
- Any pending Carta transactions have been completed
Contact Carta’s support to cancel, and download everything before you do.
Common Questions
Can I keep using Carta while Mantle sets up my cap table?
Yes, and you should! Don’t cancel Carta until your Mantle cap table is fully set up. Most founders run both during migration, then cancel Carta once everything checks out.
Do I need to involve my law firm?
You don’t need a law firm to run the migration, but if you do work with one, it’s worth having your attorney/paralegal do a review of the completed Mantle cap table before you cancel Carta.
Can I upgrade from Starter to a paid plan mid-migration? Yes. If you start on Starter and realize you’d rather have Mantle’s team handle it, you can upgrade and the onboarding team will take over from where you are.
Final Thoughts
Migrating a cap table isn’t the most glamorous founder task, but it’s one of those things that pays dividends over time — especially heading into fundraises, secondary transactions, or a liquidity event, where clean, portable, well-documented equity records matter enormously.
Whether you hand it off to Mantle’s team or self-serve with AI Extract, the Carta-to-Mantle path is well-worn. Most founders are fully transitioned within a week.
Have questions about your specific situation? Mantle’s support team is reachable directly and responds quickly, which is, frankly, part of why people switch.