Wrong Cost Basis from Metamask / Uniswap

The Accointing data set basis for the following transaction is low by $2,900 which has negative tax implications and seems like a bug.

Here’s the Etherscan transaction

Swap 5.526 Ether For 6,377.481 MOD On Uniswap
Transaction Fee: 0.01799955 Ether
Ether Price: $4,087.02 / ETH (at exact time of trade)

Here’s what Accointing recorded:

5/14/21 5:48 PM Withdraw API -5.526041 (ETH) MetaMask Swap
Cost Basis: 22,090.97 USD
Sales Proceed: 22,074.75 USD
Transaction Fee: 0.01799955 ETH

5/14/21 5:48 PM Deposit API 6,377.48122348 (MOD) MetaMask Swap
Cost Basis: 19,565.99 USD
Sales Proceed: N/A

A manual calculation results in an ETH sales proceed of $22,585.04 …

5.52 ETH * 4087.02 $/ETH = $ 22,585.04

… so the cost basis for MOD should be similar at around $22,500 not $19,566 as reported by Accointing.

Can this lowered basis be explained any way other than a bug? It will result in an increased capital gain of ~$2,900 when selling the MOD token.

Hey GQG, Accointing gets the coin value at the time of transaction from CoinMarketCap and not the particular exchange. Would that explain your issue?

I guess that would explain it, but that’s an unsatisfactory answer given (1) the negative tax implications, (2) given that the correct details are captured in the blockchain transaction forever, and (3) given we pay you for this service.

Why not read, digest, and report from the original source? You’re using a transaction pricing shortcut for your programming convenience and it’s costing me (and others with their token purchases) lots of unnecessary tax dollars if the tokens experience a gain because the basis you’ve calculated is potentially too low. This is especially true for transactions on Uniswap, SushiSwap, PancakeSwap, and DeFi / DEX aggregators (1inch, etc.)

I’m sure many of your subscribers don’t realize the tax implication penalty of what you’re doing by taking a pricing shortcut for your convenience, not for accuracy. I support “keep it simple, but not too simple.” Your methods are too simple. You could do better for a paid service.

Yes, I understand that crypto tax law in many respects is not settled and there’s a lot of gray area to be interpreted, especially with staking, lending, margin, etc… In the case I’ve presented, though, it’s clearly a rookie mistake. Now I’m forced to go through all of my transactions and manually correct potential basis calculation errors. Or maybe not, because it’s too much work and why I paid for this service in the first place. Guess it’s time to look around for a more professional service that collects original data and gets the details right.

We are a new company and are always growing! Thank you for your feedback! :slight_smile:
I am sorry that Accointing was not satisfactory for you.

@Matt I got a similar problem with TLM/USDT and TLM/BTC trades. The reason was that when the market opened the price was extremely volatile (quartered within minutes).
E.g. I sold ~1.2 TLM for ~1 USDT, but the cost basis and sales proceed is > 3 €, which obviously can’t be true

Is it possible to

  • either adjust the cost basis manually
  • or even better be able to use the price of the asset with higher market cap as that would save a lot of manual effort?

Unfortunately I don’t see any way to create a reasonably accurate tax report at the moment, because my taxable profits are calculated 3 times higher than they actually are.


Hey! I’m sorry to hear that. I’m going to need you to help me out with the following:

  1. Account details
  2. Screenshot of the error you received
  3. Wallet/Exchange you were using when you encountered this issue
  4. Exchange or Wallet API keys, Wallet Address or CSV used to try to replicate the error
  5. A link to this page

Please send all of this to support@accointing.com and we will try to help you out as quickly as possible.

I am having the same issue , cost basis is wrong , there is no way i made the money you claim i made , been looking for at least 2 hours to find what is wrong , i could not find it , ’
I calculated things manually and you are way off , this will cost me a lot of money in taxes

you are reporting more than double of what i make , is there any support where someone can have a look thanks

Hello @Modd, Accointing receives the value of coins from CoinMarketCap, if the price in which you paid for your coins is not the same as CMC, please consider making it an OTC transaction.