Retail investors can practice genuine impact investing in public markets — and this comparison covers four tools they commonly reach for: Ziggma, Morningstar, As You Sow, and Carbon Collective. Each takes a different route to impact, and one of them, examined closely, offers no impact mechanism at all. All four are rated here on magnitude of impact, data quality, portfolio analytics depth, and pricing.
Yes — through three documented mechanisms. The skeptic's objection is fair: buying a share on an exchange sends no new money to the company, so how can a public-market portfolio have impact?
Here are three mechanisms:
First, capital allocation moves prices, and prices move the cost of capital: companies whose shares are in demand raise equity more cheaply, borrow on better terms, and fund expansion that underpriced competitors cannot.
Second, shareholders own real rights — proxy votes and engagement that direct company behavior from the inside.
Third, sustained divestment raises financing costs for the excluded: the mechanism runs in both directions.
U.S. households hold $87 trillion in public-market wealth — the largest pool of reallocatable capital in the world. 58% of U.S. households own publicly traded stock. By comparison, the dedicated impact investing market accessible to the typical investor — private funds, development finance, green bonds — pales in size at $2-4bn (0.0023-0.0046%). Impact-focused investors have their eyes solely on this small pool of capital while ignoring the tremendous opportunity to create impact through capital in ordinary brokerage and retirement accounts.
The practical question, as the Ziggma Impact Investing Guide puts it, is what tools you use to do this well.
The table below compares Ziggma, Morningstar, As You Sow, and Carbon Collective across four practical dimensions: how each one mechanically produces impact, whether its underlying data is holding-level or aggregate, what it costs, and which investor it best serves.
That data distinction matters because ESG ratings and impact ratings are not the same thing, even though they're often used interchangeably. An ESG rating, like Morningstar's, scores how well a company manages risks to its own business — regulatory, reputational, financial. An impact rating, like Ziggma's Impact Score, scores the effect a company's business has on the world. A company can carry a strong ESG rating while manufacturing weapons or extracting fossil fuels, because ESG risk and real-world impact answer different questions.
| Tool | Impact Mechanism | Data Type | Pricing | Best For |
|---|---|---|---|---|
| Ziggma Analytics platform | Informed reallocation — holding-level data guides investor-directed trades via the Portfolio Optimizer | Stock, ETF and fund impact ratings; Portfolio and holding-level impact assessment | Free tier; full impact analytics and account linking on paid plans (7-day free trial) | Self-directed investors and any investor curious about their advisor's or 401(K) plan provider's investment allocation decisions |
| Morningstar Fund research | None used alone — measures risk to the fund, not impact from the fund (single materiality) | Aggregate fund ratings (Sustainalytics) | Free basic lookup; paid subscription for full ESG dashboards | Checking a fund's ESG risk before buying |
| As You Sow Nonprofit screeners | Exclusion at scale — free screeners fuel the divestment pressure that raises excluded industries' financing costs | Fund-level issue screens (funds and ETFs only — no individual stocks) | Free (501(c)(3) nonprofit) | Single-issue due diligence on a specific mutual fund or ETF |
| Carbon Collective Managed portfolios | Structural reallocation — divests fossil-fuel-dependent companies, reinvests in climate solutions, votes proxies | Fund-level impact assessment with focus on climate | 0.25% annual management fee plus underlying fund expenses; no minimum | Investors who want climate alignment handled for them |
Comparison reflects publicly available product information as of July 2026. Pricing and features may change — verify on each provider's site.
Ziggma's impact mechanism is informed reallocation: it provides self-directed investors with both portfolio-and holding-level impact data so they can move their capital toward companies solving real problems.
Ziggma links brokerage and retirement accounts via Plaid and Snaptrade, then scores every holding using data from ACA Ethos, measured per company rather than averaged across a fund. This includes accounts managed by an outside advisor or 401(k) provider — such as those custodied at Schwab Advisor Services or administered by Empower — giving the roughly 61 million Americans with an advisor-managed account an independent read on what they actually hold.
The metrics include an Impact Score, Global Warming Potential (GWP) in degrees Celsius, Carbon Intensity, Net-Zero Target Dates, and a Controversy Score, among others — sitting alongside the Ziggma Score's four financial pillars (Growth, Valuation, Profitability, Financial Health), so impact and quality are weighed together, not traded off.
The Portfolio Optimizer helps investors turn that data into decisions: it flags the holdings dragging down a portfolio's Impact Score, shows how any replacement shifts Global Warming Potential and sustainability alignment before the trade is made, and surfaces high-impact alternatives — while keeping portfolio quality in view, so impact improvements don't come at the cost of financial strength.
Ziggma provides the analysis; the investor makes every allocation decision and places trades through their own broker.
Morningstar's ESG Risk Rating measures risk to the fund, not impact from the fund — used alone, it produces no impact.
The rating, built on Sustainalytics data, scores how well a fund's companies manage ESG risks to their own financial performance: single materiality.
A fund can rate well while holding tobacco, fossil fuel producers, or weapons manufacturers, because the rating asks whether those exposures threaten returns, not whether the business harms the world. Morningstar remains a credible research layer for fund due diligence — but an investor seeking impact needs an impact-focused tool to supply the mechanism this one lacks.
As You Sow's impact mechanism is exclusion at scale: its free Invest Your Values screeners expose what funds actually hold, fueling the divestment pressure that raises financing costs for excluded industries.
The 501(c)(3) nonprofit's tools — Fossil Free Funds, Deforestation Free Funds, Weapon Free Funds, and others — grade any U.S. mutual fund or ETF on a single issue, with full look-through to underlying holdings. The organization compounds this with its own shareholder advocacy, filing resolutions at the companies its data exposes. The limits are structural: one fund and one issue at a time, no individual stock data, no account linking, no ongoing portfolio tracking, and no positive selection — the screeners tell you which funds to avoid, not what to own.
Carbon Collective's impact mechanism is structural reallocation, executed for you: it divests the roughly 20% of the market dependent on fossil fuels, reinvests that share in climate-solutions companies, and uses proxy voting to pressure the rest.
That is a genuine, legible impact design — capital exits the problem and enters the solution, systematically. The trade-off is self-direction: as a registered investment adviser charging a 0.25% annual management fee plus underlying fund expenses, Carbon Collective makes the allocation decisions as fiduciary. Clients don't select holdings, see per-company impact data, or apply the strategy to accounts held at other brokers — its mechanism only touches money moved onto its platform.
Match the tool to what you're actually trying to do.
If you want a free, single-issue check on one fund before buying it, use As You Sow.
If you want to research a fund's ESG risk profile before buying it, use Morningstar — but recognize that managing risk to the fund is not the same as producing impact from it.
If you want climate reallocation handled entirely by a professional, without picking stocks yourself, use Carbon Collective.
And if you manage your own brokerage and retirement accounts and want holding-level impact data across every one of them — with your own capital allocation as the impact lever — that's the self-directed case Ziggma's screener and Portfolio Checkup are built for.
