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Design Your Own Stock Index

Double lets anyone design and invest in their own stock index that’s advised, managed and tax optimized by Double.

Double
Founded:2023
Team Size:5
Location:San Francisco
Group Partner:Garry Tan

Active Founders

JJ Maxwell, Founder

Building Double. Former CTO of Liftoff Influence, Former co-founder of Jetfuel (acquired by Liftoff 2021)

JJ Maxwell
JJ Maxwell
Double

Mark Wai, Founder

Previously Growth @ Tesla, Facebook

Mark Wai
Mark Wai
Double

Company Launches

TL; DR — Design and invest in your own stock index that’s advised, managed, and tax-optimized by Double.

Historically, access to sophisticated finance tools like direct indexing and tax loss harvesting has come at a steep cost and only through exclusive financial advisors. We are on a mission to revolutionize investing by providing world-class portfolio tools to everyday investors without any AUM fees.

Key Features

  • Direct Index into 20+ ETFs: Build an elite portfolio with the ability to tilt towards specific sectors, industries, themes, or even custom groupings like all YC publicly listed companies.
  • Daily Tax Optimization, Rebalancing & Potential Tax Loss Harvesting: Our optimization engine keeps your portfolio on track by factoring in drift, taxes and transaction costs. If your account qualifies, our tax-loss harvesting service aims to help you minimize your tax liability and maximize your after-tax returns.
  • Dollar-cost averaging: We allow users to move between positions at a set cadence, regardless of the market's performance, helping you reduce timing risks associated with active trading.

Example Use Cases

Work for AAPL and want to diversify away from tech?

  • Buy a direct-indexed S&P 500 Portfolio, remove AAPL entirely, and cut the rest of your tech exposure in half.

Did you know AI was going to be a big deal before everyone else?

  • Double makes it easy to tilt your portfolio towards your hunches. Pick a handful of stocks set to benefit from the Inflation Reduction Act, or some that target the booming AI and semiconductor industry, or shift your portfolio towards the explosive meme growth of Zyn.

Feeling confident in the overall market and ready to pile on the risk?

  • Follow Hedgefundie’s Adventure, which uses 3x leverage in a Stock and Bond ETF to try and increase returns. Or pick from our smart screens that target top growing companies or even a basket of the YC Public Companies.

Think we’re headed for a recession and want to take some chips off the table?

Build and backtest your own stock index!

  • Use our Stock and ETF Screeners to build your very own personalized portfolio.

Fees

Double doesn’t charge AUM fees. Financial Advisors often charge around 1% a year for tools like Direct Indexing and Dollar Cost Averaging. In a sample $1M portfolio, these fees lead to a dollar cost of $1,800,000 or a 24.5% overall reduction in performance over 30 years, assuming 6% growth vs. 7% growth. We aim to eventually make money like the commission-free trading pioneers. Our custodian Apex Clearing charges some fees which we pass on to users which you can see here.

Additional Features

  • Backtest a custom stock grouping to see its historic performance.
  • Cash sweep available: Earn 4.5% interest on your uninvested cash (as of August 5th, 2024, not a guarantee of future rates)
  • Fractional investing: Invest in over 3,000 US stocks and 1,400 ETFs for as little as $5 per share.
  • Support for Personal, Joint, and Trust Accounts
  • Daily portfolio optimization and trade execution
  • Recurring or one-time deposits via ACH or Wire
  • ACAT Transfer in an existing brokerage account

Get Started Today

We’re live at https://double.finance. Sign up for a Double account today and start building your own stock index. Please reach out to founders@double.finance with any feedback or questions!

YC Sign Photo

YC Sign Photo

Selected answers from Double's original YC application for the W24 Batch

Describe what your company does in 50 characters or less.

Build and invest in custom ETFs

What is your company going to make? Please describe your product and what it does or will do.

Double is building a smarter brokerage account for sophisticated retail investors.

Double allows you to build a personalized portfolio by direct indexing into popular ETFs that you can customize. Or build a custom strategy that targets things like “Fertilizer” or “Regional Banks”. Allocate percentages of your portfolio towards strategies over time, and let Double automate things like tax loss harvesting and rebalancing. Double shows users portfolio theory concepts like the efficient frontier, backtesting and monte carlo simulations right in the account.