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Context

By convention, most NFT trades only involve one currency, where the buyer senders erc20/native token to purchase an NFT from the marketplace. This is the case for most marketplace protocols and transactions currently. The Seaport marketplace contract allows users to create and fulfill orders for ETH, ERC20, ERC721, and ERC1155 items.

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Implication: Multi-currency NFT Trades

The flexibility of Seaport means that there are infinite combinations of trade setups that can happen. As a result, it is possible to have multiple currencies offered for an NFT trade. This constitutes a small fraction of all Seaport trades. When a seaport transaction consists of mixed trades of tokens/NFTs, it is also difficult to attach a price to an NFT traded within the mixed trade. The set-up becomes more like a barter trade.

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Phising Transactions

This flexibility also exposes more attack vectors for malicious actors who utilize weird trade setups to phish/create fake volume. An example of such a phishing transaction is shown below:
Multi-currency trade flagged as a phishing transaction. Note that the recipient of the ERC20 tokens also received the NFT.

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Most multi-currency trades were flagged as phishing trades

Most of the multi-currency transactions on Ethereum Opensea Seaport trades were linked to phishing addresses labeled on Etherscan. Like the one shown above. These transactions involve the transfer of multiple NFTs with minute amounts of ERC20 tokens + ETH. Hence, the USD value of the individual NFTs in such trades will not be reflected accurately. In our current NFT trades model, the prices are represented as NULL.