A practical comparison of five platforms self-directed investors actually use to decarbonize their portfolios — what each one is best at, and where each one falls short.
Sustainable investing has a terminology problem. ESG, SRI, impact investing, values-based investing — the labels are often used interchangeably, but the platforms behind them work in fundamentally different ways. That difference matters when you're deciding where to put your money.
Most mainstream platforms take a traditional ESG risk approach: they screen companies or funds using environmental, social, and governance scores, primarily to identify financial risks — not to measure real-world outcomes. You avoid the obvious bad actors, but you don't necessarily know whether your portfolio is doing anything positive.
A smaller set of platforms take an impact and sustainability focus: they go further, tracking measurable outcomes like carbon emissions, global warming potential, net zero alignment, and social impact metrics at the holding level. The goal isn't just risk avoidance — it's building a portfolio that actively reflects your values.
Neither approach is wrong. But knowing which one a platform uses changes how useful it is to you. Below, we've reviewed 10 platforms across three categories — independent analytics tools, brokers, and asset managers — and flagged the approach each one takes.
The underlying ratings infrastructure most platforms on this list rely on. Morningstar's sustainability ratings and Sustainalytics' ESG risk scores measure how much ESG factors represent a financial risk to a company — not how positive its real-world impact is. The free fund screener on Morningstar.com lets you filter by sustainability score, carbon risk, and controversy level. If you want to verify ESG claims independently before investing anywhere, start here.
Where most platforms show ESG scores at fund level, Ziggma breaks them down holding by holding — impact scores, global warming potential in °C, net zero target status, climate action ratings, and controversy scores all visible within your actual portfolio. This is impact-focused analytics, not ESG risk filtering: you can see exactly how each stock or ETF contributes to your overall sustainability profile, spot greenwashing, and make targeted changes. Works alongside any broker through - even for investors tracking multiple investment accounts.
Best for: self-directed investors who want holding-level impact visibility on top of their existing brokerage
One of the few brokerages built around ESG data and shareholder engagement from the ground up. Fennel covers 200+ ESG indicators per company — carbon footprint, shareholder rights, human rights protections, board diversity — alongside past and upcoming shareholder vote data. No payment for order flow, no securities lending. A $4.99/month subscription covers everything. The company is small and seed-funded; some user reviews flag execution issues — factor that in when considering it as a primary brokerage.
Best for: ESG-first investors who want integrated ESG data and trading in one place.
For experienced traders who don't want to sacrifice flexibility. IBKR lets you build a values-aligned portfolio from scratch — filtering on ESG criteria like board diversity, clean energy focus, or sector exclusions — at some of the lowest fees in the industry. Its ESG screening is risk-oriented rather than impact-focused, so pair it with Ziggma if you want deeper sustainability analytics on top of IBKR's trading infrastructure.
Best for: active traders who want full flexibility with ESG filtering and low costs.
The go-to for hands-off investors who want sustainable exposure without picking stocks. Its dedicated socially responsible portfolio automatically excludes fossil fuels, weapons, and tobacco, with auto-rebalancing and tax-loss harvesting. The ESG lens here is primarily about exclusions and risk screening, not measuring real-world impact. At 0.25% annually, it's well-priced for fully managed ESG investing.
Best for: passive investors who want set-and-forget ESG management with sector exclusions.
As You Sow is a non-profit shareholder advocacy organization that publishes free, web-based fund screeners — including Fossil Free Funds, Deforestation Free Funds, and Invest Your Values. The Fossil Free Funds tool lets investors look up any mutual fund or ETF and see its exposure to fossil fuel companies, deforestation risk, and a handful of related climate dimensions. The data is sourced and methodologically transparent, and the tool is widely used in climate-focused advocacy and divestment campaigns.
Best for: investors who want ESG risk management alongside sophisticated long-term financial planning.
Public.com adds a social layer to sustainable investing — follow other investors' ESG-aligned portfolios, see their rationale, and discover impact-focused stocks through community discussion. ESG data is sourced from third-party providers rather than proprietary analysis. No payment for order flow is a plus.
Best for: newer investors who want community context around sustainable choices
An Australian ethical share trading platform built explicitly around shareholder activism. SIX publishes ESG profiles on all major ASX-listed companies and ETFs, and organises campaigns on climate, nature, and social justice — letting investors use their shareholdings to push companies toward change. Impact-focused by design rather than just screening for risk. Currently covers ASX-listed securities only.
Best for: Australian investors who want to combine ethical investing with direct shareholder advocacy
Goes beyond stock selection by incorporating green bonds and climate-focused fixed income, and engages in shareholder advocacy on behalf of investors. Collective voting power is used to push companies toward more aggressive climate action — a genuine impact orientation, not just ESG risk filtering. Low $50 minimum, 0.25% advisory fee, and over $225M under management.
Best for: climate-focused investors who want capital and votes pushing companies toward net zero
Launched in 2000 as the world's first sustainable robo-advisor, EarthFolio invests exclusively in funds rated Sustainable or Responsible — every dollar, no exceptions. It's less feature-rich than newer platforms but its purity of commitment is unmatched. A reliable anchor allocation for investors who want guaranteed ESG integrity in the fund selection layer.
Best for: investors who want total sustainability assurance with zero compromise on fund selection
Climate-aligned investing isn't one decision — it's a sequence of them, and the right platform depends on where you are in the process.
If you're checking a single fund or ETF before buying, As You Sow's Fossil Free Funds tool is the most accessible free option, and Morningstar adds broader fund coverage and analytic depth at a subscription tier.
If you want climate-aligned investing managed for you, Carbon Collective is the most established US robo-advisor in the category.
Already at Interactive Brokers? Their Impact Dashboard has certain climate features at no extra cost.
Ziggma is built for self-directed investors who want the full picture — temperature alignment, per-holding net zero target tracking, and a climate-aware stock and ETF screener that combines fossil-fuel exclusion and renewables thresholds with financial-quality filters — across all their accounts.
