Using OpenSecrets and Other Databases to Investigate Dark Money

Investigating dark money in American elections requires moving beyond official campaign finance filings to trace funds flowing through nonprofit organizations that face no legal obligation to disclose their donors. Databases maintained by organizations like OpenSecrets (Center for Responsive Politics) aggregate IRS filings, Federal Election Commission reports, and state-level disclosures into searchable tools that researchers, journalists, and civic advocates rely on to map spending patterns. This page covers how those databases are structured, what they can and cannot reveal, and how investigators apply them to common research scenarios. Understanding these tools is foundational to any serious engagement with the broader landscape of dark money spending.

Definition and Scope

Dark money investigation databases are structured repositories of public financial disclosure records — primarily IRS Form 990 filings, FEC independent expenditure reports, and electioneering communication filings — compiled and cross-referenced to expose connections between nonprofit spending and electoral activity. The central challenge is structural: 501(c)(4) social welfare organizations and 501(c)(6) trade associations are not required by federal law to disclose donor names publicly, meaning the original funding source is often invisible in official records (IRS Publication 557).

OpenSecrets, operated by the nonprofit Center for Responsive Politics, is the most widely cited of these databases in academic and journalistic contexts. It tracks outside spending groups, compiles 990 data for 501(c)(4) organizations involved in dark money, and flags when organizations report no public donors despite spending millions in election cycles. The database covers federal election cycles back to 1990 for many data categories.

Additional databases relevant to dark money investigation include:

• ProPublica Nonprofit Explorer — Hosts IRS Form 990 filings for approximately 1.8 million tax-exempt organizations, searchable by name, EIN, or state.
• FEC.gov — The Federal Election Commission's official disclosure portal, covering independent expenditures, electioneering communications, and Super PAC contributions.
• FollowTheMoney.org — Maintained by the National Institute on Money in Politics, focuses on state-level campaign finance data across all 50 states.
• IRS Tax Exempt Organization Search — The authoritative federal registry for tax-exempt status determinations and basic filing histories.

The distinction between these tools matters: FEC.gov captures spending that crosses the legal threshold for "express advocacy" or "electioneering communications" within 30 days of a primary or 60 days of a general election (52 U.S.C. § 30104), while 990 filings capture organizational revenue, expenditures, and program descriptions — but not donor identities at the federal level for 501(c) nonprofits.

How It Works

A standard dark money investigation proceeds through 4 discrete stages:

1. Identify the spending event. Locate an FEC electioneering communication or independent expenditure report naming a nonprofit as the spender. OpenSecrets aggregates these by cycle and organization under its "Outside Spending" section.
2. Pull the 990 filings. Cross-reference the organization's EIN on ProPublica Nonprofit Explorer or the IRS Tax Exempt Organization Search to retrieve annual 990 filings. Schedule I of the 990 lists grants paid to other organizations, which can reveal pass-through funding structures.
3. Map organizational relationships. Cross-check shared addresses, officers, and grant recipients across multiple 990 filings. OpenSecrets maintains specific pages for known donor networks such as the Koch network and Crossroads GPS that pre-aggregate this mapping.
4. Consult state disclosures. For state-level races, FollowTheMoney.org and relevant state election agency portals fill gaps not covered by FEC filings, since state dark money disclosure laws vary significantly in scope.

The critical constraint throughout is the donor wall: even a fully reconstructed financial map typically terminates at the 501(c)(4) or 501(c)(6) entity itself, because those organizations file a Schedule B (donor list) with the IRS that is not publicly released (IRS Instructions for Form 990, Schedule B).

Common Scenarios

Scenario 1 — Tracing a single ad buy to a network. A television ad runs in a Senate race. The FEC electioneering communication report names "XYZ Action Fund" as the buyer. A 990 search reveals XYZ Action Fund received 80% of its revenue from a single grant from a larger 501(c)(4). That larger organization's 990 shows it, in turn, received grants from a trade association. This chain — documented entirely through public filings — exemplifies the layering described in dark money investigative journalism practice.

Scenario 2 — Judicial confirmation spending. Nonprofit spending around Supreme Court confirmation hearings does not trigger FEC disclosure requirements because it does not constitute express advocacy for a candidate. Dark money in Supreme Court confirmations is therefore documented primarily through 990 filings and voluntary disclosures, making ProPublica Nonprofit Explorer the primary tool rather than FEC.gov.

Scenario 3 — State ballot measure funding. Several states require independent expenditure disclosure for ballot measure campaigns, but the threshold and covered entities differ by jurisdiction. FollowTheMoney.org aggregates dark money in ballot measure campaigns across state lines where data is available.

Decision Boundaries

Not all research questions are answerable through public databases, and knowing the limits prevents false conclusions.

What databases can establish:
- Organizational spending amounts and recipients
- Shared infrastructure between organizations (addresses, officers, registered agents)
- Timing correlations between 990 grant payments and FEC-reported expenditures
- Whether a group qualifies as a recognized dark money research organization target based on spending-to-revenue ratios

What databases cannot establish without additional reporting:
- The identity of ultimate donors to 501(c)(4) or 501(c)(6) organizations
- Intent behind organizational relationships (coordination vs. coincidence)
- Whether a group's "primary purpose" crosses the IRS threshold for political activity under IRS rules for dark money nonprofits

The comparison between OpenSecrets and FollowTheMoney.org illustrates a core decision boundary: OpenSecrets is optimized for federal election cycles and provides the deepest cross-referencing of FEC and 990 data at the national level, while FollowTheMoney.org covers 50-state data with greater granularity for dark money in state elections but with less synthesis of organizational network connections.

Researchers approaching this topic for the first time should begin at the dark money authority index to establish baseline definitions before moving into database work, as the legal distinctions between spending categories determine which disclosure regime — and therefore which database — applies to a given investigation.