Calling this merely a trade is a terrible distortion of what happened. The Atlantic slave trade was a violent system of human enslavement and exploitation, not merely an exchange of commodities.
Ships, investors, insurers and creditors financed voyages and plantations while the people enslaved bore immeasurable human harm. Every insurance policy and loan sat inside a violent system of enslavement.
Financial records can reveal profits and losses but must never be treated as a complete measure of a system built on coerced labor. Profit-and-loss books cannot account for a stolen life. That limit matters.
A failed voyage didn't make the wider institution any less brutal. Participation and profitability varied across places and periods; a particular merchant's failure does not diminish the wider system's scale or cruelty.
How should economic historians use ledgers without allowing the vocabulary of finance to erase the people subjected to it?