There are tons of people who are curious about the tax consequences of opening/using a Maker CDP. It's one of the most common questions asked on /r/makerdao and the Maker Rocket Chat. Although I don't have any CDPs, I've been curious myself.

The technical steps are as follows:

1. Wrap your ETH into WETH, which I argue should probably not be a taxable event. (They have the same economic properties, just different technical ones)
2. Wrap your WETH into PETH (Pooled ETH) which is a token representing a share in all the collateral that the MakerDAO system has. Since the pool can grow or shrink, and thus has different economic properties, I'm thinking this is a taxable event. I've heard arguments against that, though.
3. Lock your PETH into a CDP. This is probably not a taxable event.
4. Take out a DAI loan from the CDP. Here's where my layman's knowledge ends. I would hope that it's legally considered a loan, but it's not in USD, or even technically a currency.
5. Repay the loan, which requires briefly purchasing MKR to pay the interest on it. Also, the effective principle will have fluctuated--you might have taken out the loan when DAI was trading at $1.02, and now it's $0.97.

This is not counting the possibility of one's collateral falling in value, whereupon some or all of it will be repossessed by the system. I'm sure there's something in the tax code somewhere about this sort of thing, but I haven't a clue where.

EDIT: Also, can you deduct the interest on the CDP--say, if it was owned by your business?