Over at https://money.stackexchange.com/q/146575/75566 we haven't come up with an English word that unambiguously means "change in wealth over time." My perhaps naïve first shot at this was "income." It turns out that "income" is overloaded and does not communicate what I think it does. For instance, some very wealth people have zero income. What world in English could we use to unambiguously talk about someone's "change in financial wealth over time?" Talking about a person's "yearly income" brings up too much debate about what income is, exactly; so, what word could we use to introduce clarity to the sentence.
While Bill Gates recorded a taxable income of $0 last year, over that same period his __________ was $3.5 billion; that means he paid zero taxes on his $0 income while increasing the financial wealth that he controls from $30 billion to $33.5 billion.
What is the one English word that can fill in the blank?