Uniswap, Andreessen Horowitz (a16z), and Paradigm have joined a coalition of decentralized finance groups backing a court challenge to Illinois' 0.2% digital asset tax. The coalition filed an amicus brief opposing the state's draft broker rules, arguing that the proposal would require fee-charging decentralized exchanges and their interfaces to collect the levy. An amicus brief allows non-parties to a case to file supporting arguments, and this filing broadens the dispute's backers beyond the trade associations that originally sued.

The DeFi Education Fund announced the filing on X on Nov. 12:

Illinois' Digital Asset Tax Act is Unlawful and Unenforceable DEF, @a16z, @paradigm, @Uniswap & 14 co-signers joined together to submit an amicus brief supporting @BlockchainAssn, @crypto_council, and @digitalchamber's challenge to the Illinois' Digital Asset Tax Act. 👇 pic.twitter.com/mkoOqPoni1

— DeFi Education Fund (@fund_defi) November 12, 2026

The Crypto Council for Innovation and the Blockchain Association brought the underlying lawsuit in Sangamon County Circuit Court. The DeFi Education Fund, Aave Labs, and Chainlink Labs also signed the amicus brief, alongside 14 additional co-signers.

Federal Support for the Challenge

According to the Blockchain Association, the U.S. Justice Department filed a statement of interest in the case on Nov. 6, arguing that the crypto tax undermines federal policy on digital assets. A statement of interest is how the federal government signals its position in pending litigation, adding a federal voice to the challenge ahead of the industry's amicus filing. The U.S. Chamber of Commerce and the Securities Industry and Financial Markets Association filed a separate brief the same day, extending the opposition beyond crypto-native groups.

How the Draft Rules Would Affect Brokers

Miles Jennings, a16z's policy chief, said autonomous software cannot collect the levy — the crux of the industry's objection, since protocols and interfaces without a central operator would have no clear party to remit the 0.2%. An October letter flagged a draft provision that would require brokers to store customers' private keys; the brief's signers warned of theft risks and proposed requiring public keys instead.

Background on the Illinois Levy

Gov. JB Pritzker signed Illinois' 0.2% crypto tax into law on June 16, 2026. The levy covers qualifying digital asset exchanges, transfers, and storage services, even when no sale or profit takes place — meaning the 0.2% can attach to transfers or storage alone, not only sales. In October, a court-approved agreement delayed its enforcement from January 1 to July 1, 2027, while legal challenges continue, leaving the Sangamon County Circuit Court case as the timeline to watch for how — or whether — the levy takes effect as written.

The dispute also follows a related federal development: an IRS rule would have required certain DeFi platforms to report user transactions, but President Donald Trump signed a congressional resolution repealing it in April 2025.