Software in the Public Interest revenue was $685,055 in 2024, and the deficit is not SPI's

Quick answer (September 2026). Software in the Public Interest, Inc. reported total revenue of $685,055 in 2024, $463,221 in 2023 and $485,337 in 2022 on its Form 990. Its independently audited statements report a different and higher figure for the same years: $707,325 in 2024 and $501,254 in 2023. Expenses were $925,737 in 2024, so the return shows a deficit of $240,682, the third in a row. That deficit is almost entirely money belonging to the projects SPI holds funds for, not to SPI. Over 2023 and 2024 the restricted balance fell $624,176 (down 24.08%) while SPI's own unrestricted reserves rose $176,596 (up 46.22%), from $382,103 to $558,699. Debian alone accounts for 70.80% of the restricted decline.

Software in the Public Interest is the New York non-profit that has quietly held the bank account for large parts of the free software world since 1997. It lists 48 associated projects, among them Debian, Arch Linux, PostgreSQL, FFmpeg, LibreOffice and OpenZFS. It has zero employees. Its 2024 return reports 1,500 volunteers.

If you search for its revenue today, the first result is a Wikipedia infobox whose newest figure is from 2022. Two more returns have been filed and published since. This piece reads all of them, plus the audited statements and SPI's own general ledger, and reconciles the three against each other.

What the three sources are

SPI is unusually well documented, and it is worth saying so plainly before any criticism follows.

1. The Form 990. Filed with the IRS, tax year ending 31 December. I read the filed XML from the IRS release for tax years 2023 (object ID 202413069349300531) and 2024 (object ID 202503219349304305).
2. The audited financial statements. SPI's statements are audited, which matters more than it sounds, and I come back to it below. The 2024 audit was signed by Eisenkraft CPA PLLC on 12 November 2025, with an unmodified opinion.
3. SPI's own ledger. SPI publishes a machine-generated treasurer's report every month, with a per project breakdown, going back to January 2016. The most recent is June 2026.

Almost no organisation of this size publishes all three. Most publish none.

Grading the answers that already exist

Wikipedia is two filed years behind. Its infobox lists $723,853 (2020), $522,719 (2021) and $485,337 (2022), sourced to ProPublica with an access date of June 2023. The 2023 and 2024 returns have both been filed and are both public.

ProPublica's page is correct and current. It shows fiscal year ending December 2024 with revenue $685,055, expenses $925,737, net income minus $240,682 and net assets $2,526,740. Every one of those four figures is exactly right. Credit where it is due.

There is a wrinkle worth flagging for anyone building on ProPublica's API rather than reading its pages. The API's filings_with_data list stops at tax year 2023, and 2024 sits in filings_without_data. The 2024 figures are still reachable, but only from the organisation level revenue_amount field and from latest_object_id, which names the filing. A downstream tool that iterates the filings list will quietly report 2023 as the latest year. That is the mechanism by which stale non-profit figures propagate around the web.

What none of the existing answers publish is the only number that actually explains SPI: the split between the projects' money and SPI's own.

Two revenue figures, and they grow at different rates

Because SPI's statements are audited, Schedule D of the Form 990 has to reconcile the return against them. That reconciliation publishes a second revenue figure for the same year.

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The gap is not an error. Unrealised investment gains belong in a GAAP statement of activities and are excluded from Form 990 revenue. What it changes is the growth rate you quote. On the return, SPI's revenue grew 47.89% between 2023 and 2024. On the audited statements, it grew 41.11%. Both are true. They are simply answers to different questions, and only one of them is the number every aggregator republishes.

The same split applies to the deficit: the return says minus $240,682 for 2024, the audited statements say minus $218,412, and the $22,270 difference is the same unrealised gain.

The line that changes the story

Part X of the Form 990 splits net assets into two lines: without donor restrictions, and with donor restrictions. For an ordinary charity this is bookkeeping. For a fiscal sponsor it is the whole picture, because the restricted line is other people's money.

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Read the total column alone and SPI lost $447,580, or 15.05%, in two years. Read the split and the two halves move in opposite directions. The projects' money fell $624,176. SPI's own money rose $176,596, which is a 46.22% increase.

So the deficit on the face of the return is not SPI spending beyond its means. It is Debian, X.Org, LibreOffice and others spending funds they had already raised and parked. An organisation whose job is to hold money for other people will report a deficit every time those people spend, and a surplus every time they fundraise, and neither tells you anything about the sponsor.

I want to be careful here, because this is a correction that could easily be over sold. SPI genuinely did spend more than it took in on a Form 990 basis in each of 2022, 2023 and 2024. The point is that the line is not measuring what a casual reader assumes it measures.

SPI's own ledger names the project

This is where SPI's transparency goes well past its peers. Note 5 of the audited statements gives a per project table of restricted net assets, with beginning balance, additions, releases and ending balance. SPI's own monthly ledger gives the same thing, in cents, more recently.

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Debian is the story. Its balance fell from $697,034 to $255,098 in two years, a decline of 63.40%. In 2024 alone Debian added $103,926 and released $397,870. That single release figure is 45.05% of every dollar released from restriction across all of SPI's projects that year, and Debian's two year fall is 70.80% of the entire restricted decline.

A second thing happened while nobody was looking. Arch Linux overtook Debian as the largest project balance SPI holds. At the end of 2023 Debian was ahead by $108,902. At the end of 2024 Arch Linux was ahead by $191,244. The crossover happened during 2024, and I have not seen it reported anywhere.

Two smaller movements are worth noting because they are large in percentage terms. NTPsec fell 69.99% in 2023, from $135,684 to $40,711, and has been flat since. ArduPilot has been drawn down steadily across the whole period.

One row in that table needs a caveat. X.Org is no longer an SPI associated project. The board passed a removal resolution dated 14 April 2025, and X.Org does not appear on the current project list. SPI's own ledger nonetheless still carries an X.Org restricted balance, $144,395.04 at the end of 2025. That is consistent either with a wind down that has not finished or with funds still awaiting transfer, and the published documents do not say which, so I am recording it as a measurement rather than drawing a conclusion from it.

What SPI itself actually runs on

Strip out the projects and SPI is a very small organisation with an unusual funding mix. In 2024 its unrestricted support and revenue, before any release from restriction, was $213,444. Of that, $122,862 was investment income, or 57.56%.

Its general and administrative expense for the year was $124,076. So SPI's investment income covered 99.02% of its own overhead. The 5% fee it charges on donations, formalised by board resolution in December 2023, is doing less of the work than the endowment like balance it sits on.

The dependence on restricted giving is near total: of $542,158 in cash contributions in 2024, $493,881, or 91.10%, arrived earmarked for a named project. Only $48,277 was unrestricted.

Two other details from the return that are easy to miss. SPI reported a grant refund of $100,000 in 2023 and $150,187 in 2024, in Part IX line 24. And its public support percentage, the test that keeps it a public charity rather than a private foundation, moved from 76.41% to 84.35%, comfortably clear of the 33.33% threshold in both years.

The runway question, and why I am not answering it the usual way

The obvious calculation is unrestricted net assets divided by total expenses. For SPI that would be $558,699 against $925,737, or about seven months. That number is meaningless and I am not publishing it as a runway. Total expenses include all the project spending that is funded by restricted assets. Dividing money SPI can spend by money it mostly cannot is comparing two unrelated quantities.

SPI answers the question properly itself, in Note 4 of the audited statements. Financial assets available for general expenditure within one year are $505,794, being total current financial assets of $2,473,835 less the $1,968,041 that carries donor restrictions. The organisation states its goal as maintaining enough to meet 90 days of operating expenses. Ninety days of 2024's total expenses is roughly $228,275, so SPI is holding about 2.2 times its own stated target. Against its general and administrative cost alone, $505,794 is a little over four years.

That is a genuinely healthy position, and it is the opposite of what the headline deficit suggests.

One number that is not in any filing yet

SPI's monthly ledger runs ahead of the IRS. The June 2026 report carries opening balances for 2026, which are the closing balances for 2025, and no Form 990 for 2025 has been filed.

On SPI's own books, total net assets at 31 December 2025 were $2,686,616.75, up $159,876.82 on the year. Unrestricted rose to $628,354.83 and restricted rose to $2,058,261.92. Both halves rose for the first time in the period covered here, which means 2025 reversed the three year slide.

Two caveats, and they matter. The monthly report labels itself a draft, and it is a raw accounting export rather than an audited statement. Until the 2025 return and audit appear, treat it as SPI's own unaudited books rather than a filed figure.

By the June 2026 report, Arch Linux held $467,329.17 against Debian's $207,656.66, so Arch now holds 2.25 times what Debian does. OpenSSL, which joined SPI in August 2025, had already paid out its entire $24,235.60 balance as a grant in the first half of 2026.

The audit: 37 checks, 37 exact

Every arithmetic relationship I could test across the two returns, the two audits and the ledger reconciles exactly. That includes all three Part X splits footing to their totals, both net asset roll forwards once Schedule D's unrealised gains are applied, both Part IX functional expense columns footing, the per project roll forwards for Debian, Arch Linux and FFmpeg, the liquidity note, and the reconciliation between the audit's line groupings and the return's. Two examples of the last: the return's $547,372 of contributions is the audit's $542,158 of cash contributions plus $5,214 of other income, and the return's $126,058 of investment income is the audit's $122,862 plus $3,196 of foreign currency gains.

Most usefully, the three sources agree on the balance sheet to the dollar. SPI's ledger puts net assets at 31 December 2024 at $2,526,739.93 with $558,698.86 unrestricted. The return says $2,526,740 and $558,699. The audited statement of financial position says the same.

I found no defect worth reporting. What I found instead were two traps for anyone repeating this work.

The labels move between years. In Part IX line 24, the largest line in 2023 is "INFORMATION TECHNOLOGY" at $120,804. The largest line in 2024 is "SERVICES" at $195,991, a label that does not appear in 2023 at all, while information technology falls to $103,275. They are not the same line and should not be compared as one. Similarly, "Debian Conference" is its own row in the 2023 audit's Note 5, closing to zero, and is simply absent from the 2024 table.

The newest document is actually linked. I check this on every filing I read, because an unlisted newest filing is usually why public answers stop years early. SPI passes cleanly. Its treasurer page links Form 990s for every year through 2024 and audited statements for every year through 2024, and probing for monthly reports after June 2026 returns nothing, so the most recent report really is the most recent one. That is a low bar and a surprising number of organisations fail it.

One small observation offered as a fact rather than a criticism: the firm that audits SPI's statements, Eisenkraft CPA PLLC, is also the paid preparer named on its Form 990. This is common practice for organisations of this size and is disclosed on both documents.

What this means if you fund open source

If you donate to Debian or Arch Linux through SPI, your money is in the restricted column and cannot be spent on SPI's own operations. If you want to fund the sponsor itself, that is the 5% fee or an unrestricted gift, and the figures above suggest the sponsor is currently funded more by its investments than by either.

And if you are reading a headline that says a fiscal sponsor is losing money, check the split before you worry. For SPI over 2023 and 2024, the sponsor was getting stronger the whole time the total was falling.

The mirror case is worth a look. NumFOCUS, the fiscal sponsor behind NumPy, pandas and Jupyter, leaves that same Part X line blank on its 2023 and 2024 returns, and where SPI's unrestricted reserves rose 46.22%, NumFOCUS's fell 94.01%. Two organisations doing the same job, with opposite balance sheets and opposite disclosure.

Sources. SPI treasurer page and document archive; 2024 audited financial statements; June 2026 treasurer's report; SPI associated projects list; ProPublica Nonprofit Explorer, EIN 11-3390208. Form 990 figures are from the IRS filed XML for tax years 2023 and 2024.