It’s not always easy to understand why super PACs do some of the things they do. Most of what they do is pretty clearly intended to elect or defeat a candidate, like spending on ads or staff, but sometimes they do strange things — like giving other super PACs money. In the last FEC filing, we saw a few super PACs on both sides making some odd transactions with other super PACs.

There is a web of active Ted Cruz super PACs; at least eight, at our last count. Three of those — Keep the Promise I, Keep the Promise II and Keep the Promise III — are almost entirely funded by single large donations from one individual or family. Keep the Promise I received $11 million from Robert Mercer; Keep the Promise II raised $10 million from Tony Neugebauer; and Keep the Promise III got $15 million from members of the Wilks family.

But sifting through the disclosure forms of Keep the Promise PAC — a distinct group which raised $2.5 million in 2015 — is what we’re interested in. There’s a strange detail in their latest FEC filing, released on Jan. 31: Keep the Promise PAC received $200,000 from Keep the Promise III on June 8; then, on Sept. 28, Keep the Promise PAC sent $200,000 back to Keep the Promise III. Why did they do that? We reached out for comment, but received no response. Perhaps the group was trying to inflate the total receipts that they knew would likely be covered by journalists, but it also meant both PACs technically “spent” more.

Democratic super PACs also made some back-and-forth transfers. Correct the Record, a pro-Clinton super PAC, received $1 million from Priorities USA, another pro-Clinton super PAC that generated $25 million in the last half of 2015. However, Correct the Record is explicitly coordinating with the Clinton campaign — which it says is legal because it isn’t making independent expenditures — and Priorities USA is not. One thing to note is that David Brock, who runs Correct the Record, is also on the board of Priorities USA — presumably, this collection of pro-Clinton groups felt the coordinated activities of Correct the Record were valuable and needed more funds.

Correct the Record also gave $400,000 to American Bridge 21st Century, a super PAC that focuses on opposition research against the GOP. (It’s also run by Brock, and it’s located in the same offices.) In the second half of 2015, American Bridge 21st Century also continued to take a lot of its funding ($1.6 million, or 40 percent) from the American Bridge 21st Century Foundation, a connected 501(c)(4) nonprofit which doesn’t have to disclose its donors. The super PAC told The Wall Street Journal that this covers “shared expenses” like staff and news subscriptions, and it’s not clear if it’s the same staff working on both 501(c)(4) activities and super PAC activities. We reached out to American Bridge to clarify this, but our email was not returned.

Though super PACs are required disclose their transactions, the strange money moving mechanics of super PACs continue to blur the lines of coordination — and make following the money that much more difficult.