Sharing [Donors] Is Caring

tracking donor behavior across Senate candidates with FEC data

I have a long running interest in political donors. Not just because money is nice -- I am actually not very helpful to your average fundraising operation, except to periodically forward them poll results-- but because political donation as a behavior is really weird. It’s somewhere between charity and Kickstarter, where you may or may not get anything, but you feel like you’re part of a group. This is doubly true for small dollar donors, who are certainly not getting invited to a dinner or getting a photo with the candidate for their 20 bucks. [although, I think the “donate to enter a lottery for a visit with the candidate” promotions tend to do well]

So who are these people? I am talking about Democratic donors, because I don’t care to help Republicans win elections, and also because ActBlue is a far better source of data for this than WinRed.

They are, on the whole, of average income, and their contribution sizes reflect that (this is obvi somewhat tautological). They’re very liberal , they’re a bit more female than average, they’re heavily educated, and they tend to donate in the aftermath of big events. The NBER paper on this (here) has the best bibliography, but a lot of the work on this is a bit dated. I don’t have a strong reason to believe these characteristics have changed, though.

[A note to my future self, I should really try using the Cooperative Election Study data to look at donor characteristics more. That seems to be the option for people who don’t have a voter file on hand. ]

The other thing of note is that small dollar donors tend to give more than once. Campaigns heavily push recurring donations (which has raised some valid concerns about scam-like behavior), but in addition, donors tend to give to multiple candidates. In 2020, there was enormous overlap between the competing primary campaigns. Some of this can probably be attributed to how lists of contact information are handled (i.e. frequently passed around and sold between campaigns and orgs), but not all of it.

Donors are a pretty small group. OpenSecrets thinks that around ~1% of the population gives over 200 dollars to a campaign. The ANES reports that around 15% of people gave money to help a campaign in 2024, including 21% of Democrats. We know the number of people donating to campaigns in midterm years is lower, especially before the general election approaches.

But *how small* is this group? What does the Venn diagram of candidate donor lists look like? How much are we recycling the same people from campaign to campaign, and how much are we bringing in new folks?

The answer to this is nominally knowable, but requires a lot of data processing. I have an okay system, but it’s not that good just yet. So instead, I’ve started with a smaller universe: Senate candidates.

Test Case: Current Senate Candidates

There are so many candidates, and ActBlue data is very large. As a starting point, I pulled together a database of donations to 13 current Senate candidates across a few key states. This involved merging ActBlue (for small donations) and candidate filings (for larger donations). By merging those datasets, you get okay coverage across the spectrum of donation size. Anyone who gave less than 200 dollars directly to the candidate is still excluded, but given how popular ActBlue is, that population is small. I would describe this database as “good enough”.

To distinguish individual donors, I am using name + zip code. This is again not perfect! Some people have folks in their zip code with the same name. Unfortunately the way campaigns report full addresses can be very messy, so I think this is the best compromise. Since this data is from a single quarter, hopefully only a small number of donors have moved and thus gotten two records with two zip codes.

A couple of the candidates in this set are running in the same primary. They still have shared donors! Shoutout to the 7k ish Talarico/Crockett donors, are you guys just really not online? Do you just want everyone to have a good time?

How Many Donors Give To Multiple Candidates?

Keep in mind this is limited to candidates *in this pool*, *in this reporting period* (Q4 2025). This is certainly less overlap than you’d see taking more time/candidates into account.

The answer is “tons”! By far the most common candidate to share donors with is Ossoff, because he has a very large number of donors. I would also guess his lists have made their way back into the Democratic ecosystem at this point, and that other candidates are fundraising from lists of Ossoff donors. He is serving as a proxy for “the Democratic donor base”, in a way. If you ran this with Harris donors, you’d have a similarly massive overlap, I bet. [Yes, on the to do list, but that donation file is *huge*.]

Eight candidates in this set got the *majority* of their donors from this shared pool. I don’t currently have a way to track which candidate was the earliest contribution from an individual (i.e. who should get credit for recruiting this person to donating behavior), so it’s hard to know if these folks are recruiting donors who then make many donations elsewhere, or benefiting from that recruitment behavior. I don’t even have a particularly good picture of lifetime donation behavior, although I think it’s a bit like voting, where doing it once strongly predicts doing it again. This sort of super high overlap was surprising to me. And you’ve gotta keep in mind, this is one quarter’s filings, so almost certainly an underestimate.

Number of donors doesn’t always match up to amount of money raised. It seems like small dollar donors are more likely to be shared than large dollar ones, so the amount of money coming from shared donors tends to be smaller than their percent of the donor population. In this set, there’s just over three thousand large dollar (1k+) donors who gave to at least 2 candidates, compared to 179k small dollar donors with the same behavior. There’s 11 people who gave $1k+ to every single candidate in this set, who must be *extremely committed* to Democratic donations*[Footnote].

That being said, most of these candidates are getting significant shares of their money from shared donors. Pappas has the highest (and I’m not sure why! Joint max-out fundraiser with someone? idk!), and Talarico sticks out with having low numbers of shared donors overall, and resulting low shared $$.

El-Sayed also sticks out, because he has a very large share of shared donors (mostly with Platner), but they aren’t responsible for the bulk of his money. If I squint, this looks like using small dollar optimized lists from similar orgs/candidates and deliberately making smaller asks? That’s pure speculation, I’m not sure.

The Full Matrix

The really cool thing we can do here is look at who has donors in common with who!

You should read row-wise, where the number in each cell is the percent of [row candidate]’s donors shared with [column candidate]. Very sorry if you’re on your phone. You may want to click through for the full interact-able one, this is pretty wide, but it does get far less interesting as you scroll to the right side of the table.

Like I said above, everyone has donors in common with Ossoff. Talarico seems to be fundraising off a different set of people than everyone else (OR, has done something weird with his reporting that is breaking my script, both are possible). There’s a Platner-El-Sayed overlap, where El-Sayed is pulling a lot of his very small $ donors (14k of them), but not that much of his money. El-Sayed seems to mostly *only* have heavy overlap with Platner, so maybe this was a list passed over? That is backed up by the fact that Platner doesn’t seem to be heavily drawing from the Ossoff pool (34k of his 168k donors). You can also see Platner intersections with McMorrow, Flanagan, and Stevens, that I am less sure how to explain.

Note: I started going down the logic puzzle route of “Platner shares X donors with Ossoff and Y with El-Sayed, but El-Sayed only shared Z with Ossoff, so the intersection must be....” and then realized I can *just check*. It’s 9,506 donors giving to Platner + El-Sayed but not Ossoff, for the record, a sizeable chunk of El-Sayed’s 34k.

I also looked into what state these overlapping donors were from. It is California for every pairing except candidates in the same state (i.e. Crockett/Talarico) and Craig/Flanagan (it’s MN, idk). There’s so many Democrats in California and they love to donate.

So What Does It Mean?

Great question. It’s interesting? It means the donor polls for all these Democratic candidates are far more shared than I expected. It could maybe let you look for heavy donor overlap as an indicator of shared fundraising practices or agencies, I guess, unclear if that works.

This also gestures towards donation behavior as an expressive act rather than something particularly tied to a candidate. There’s been some good writing on “rage donating” and you always see giant spikes during dramatic news events. It seems like giving small-$ donations is less reasoned ideological support and more...cheering?

Also, the super high donor overlaps gives me even more heartburn about the churn and burn strategy of small dollar fundraising. If the donors you’re hitting with texts are part of this shared pool, your bad behavior risks ruining it for everyone. Then again, the fact that these donor populations still exist means they haven’t become burned out yet, so perhaps they’re self selecting for liking that sort of messaging? I am skeptical. If you work for a fundraising firm and you have existing analysis on lifetime donor behavior and burnout rates that I can see, pretty please let me write about it, I will leave you anonymous.

I previewed this for a couple folks, and immediately got interesting follow up questions (mostly about expanding the pool of included candidates). If you also have interesting questions, lmk, and I’ll see if I can address them. I make no promises on timing.

Notes and Caveats

As usually happens in FEC data, there’s some weirdness with donations around the max. I have a couple records that look to be over max- I think this is probably something like joint spousal contributions, or maybe oddly reported bundling. It’s not that much money in the scheme of things, so I’m not chasing it down for now.

I have in several places given precise numbers for counts of donors or amount of money. Please understand those all to be APPROXIMATE. I guarantee you I have matched incorrectly or failed to match some donors, deduped wrong, or missed refunds. It is in no way going to match internal candidate records exactly. I’m very sorry if I misstated your number of donors.

This analysis is limited to a set of candidates and a particular quarter’s filing. I have no outside information other than what you can find on twitter.

Addendum: more charts by request!

Here’s the high dollar only version. Higher overlap overall, these folks love giving to multiple candidates. Talarico is still noticably low here, not sure why.

Low dollar- less overlap overall, but some distinct spikes. Big El-Sayed/Platner spike again, this might be “lefty” small donors?