Overview
Double is a next-generation brokerage platform that empowers retail investors to build and manage personalized stock indices—akin to creating their own ETFs—without hefty fees or financial-advisor minimums. Users can select from 50+ prebuilt market and thematic strategies (e.g., “Regional Banks,” “Fertilizer,” public YC companies) or design entirely custom baskets, then automate all portfolio operations including tax loss harvesting and rebalancing for a flat $1/month fee double.finance.
Key Features
- Custom Index Builder: Assemble your own index by picking individual stocks or cloning templates of classic ETFs (like SPY), thematic plays, or sector tilts Hacker News.
- Automated Tax Loss Harvesting: The platform proactively sells losing positions to offset gains, potentially reducing annual tax liabilities double.finance.
- Rebalancing Engine: Keeps your weights on target—automatically buys or sells assets when allocations drift beyond set thresholds.
- Backtesting & Simulations: Visualize historical performance and risk via Monte Carlo simulations and efficient frontier charts directly in your account Y Combinator.
- Zero Expense Ratios: No asset-management fees—only a simple $1/month flat subscription covers unlimited trading and management double.finance.
- Transparent Analytics: Real-time dashboards show performance, attribution, turnover, and fee savings compared to traditional funds.
- Regulatory Safeguards: SEC-registered brokerage powered by Apex Clearing, with fiduciary oversight and industry-standard security protocols double.finance.
How It Works
- Sign Up & Link Account
Open a brokerage account via Double; link to your funding source. - Select or Create Strategy
Choose a prebuilt index template or craft your own portfolio from scratch. - Allocate & Launch
Set target weights, fund your account, and deploy your custom index. - Sit Back & Automate
Double handles continuous rebalancing, tax loss harvesting, and dividend reinvestment. - Monitor & Adjust
Use the dashboard to review analytics, tweak allocations, or switch strategies at any time.
Benefits of Using Double
- Cost Efficiency: Save 1–4% per year by avoiding traditional fund expense ratios and advisory fees.
- Personalization: Align your portfolio with personal convictions, ESG criteria, or thematic interests.
- Tax Optimization: Enhance after-tax returns through automated harvesting without lifting a finger.
- Educational Insights: Learn portfolio theory concepts—efficient frontier, expected returns—via interactive tools.
- Flexibility: Switch, pause, or adjust strategies instantly without penalty.
Pros and Cons
| Pros | Cons |
| Truly bespoke indices—no cookie-cutter ETFs | Flat fee may not be cost-effective for very small portfolios |
| Automated tax loss harvesting and rebalancing | Limited to U.S. equities; international assets not supported |
| No expense ratios or AUM fees—just $1/month | Market fluctuations can increase turnover and trading costs |
| Rich backtesting and risk simulations built in | Requires comfort with direct stock ownership vs. pooled funds |
| SEC-registered brokerage with fiduciary standards | Not suitable for investors needing bond or fixed-income exposure |
Use Cases
- Theme Investors: Build a “Clean Energy” or “Robotics” index that aligns with your interests.
- DIY Portfolio Managers: Replace passive ETFs with granular stock-level control and tax strategies.
- Young Tech Investors: Track and invest in public YC-backed companies via a custom “Startup Index.”
- Tax-Sensitive Investors: Maximize after-tax returns through systematic loss harvesting.
- Financial Educators: Demonstrate real-world portfolio theory and risk management to students.
Case Studies / Impact Examples
- Community Feedback: In an early “Show HN” launch, users praised Double’s intuitive interface for designing bespoke indices and the platform’s ability to outperform comparable passive funds on an after-tax basis Hacker News.
- Y Combinator Launch: Since joining YC’s W24 batch, Double has onboarded thousands of users testing custom strategies—from “Fertilizer” to “Public Tech Unicorns”—reporting average portfolio tax savings of 0.5–1% annually LinkedIn.
Pricing Information
- Flat Subscription: $1/month covers unlimited index creations, trades, tax harvesting, and rebalancing.
- No Hidden Fees: Zero expense ratios, commission-free trades, and transparent add-ons.
FAQs
What is direct indexing?
Direct indexing means you hold the underlying stocks of an index yourself, rather than shares of a pooled fund, giving you granular control and tax optimization capabilities Y Combinator.
Can I invest in fractional shares?
Yes—Double supports fractional ownership to match your exact target weights without rounding issues.
How much does tax loss harvesting save?
Savings vary by portfolio and tax bracket, but users typically see 0.5–1% boost to after-tax returns annually double.finance.
Is my money safe?
Funds are held at Apex Clearing under SIPC protection; Double operates under SEC regulations with robust encryption and security measures double.finance.
Can I close my account anytime?
Yes—withdrawals and account closures are processed promptly without exit fees.
Get Started
Ready to build your own tax-optimized index and ditch expensive fund fees? Get started with Double today for just $1/month!
