It's absolute nonsense, and something of a popular anti-Semitic trope in some radical black nationalist circles (ironically, it's also becoming popular with neo-Nazis), and is now apparently being taken up more broadly in some far left circles. It has its origins largely in the 1991 book The Secret Relationship Between Blacks and Jews, published by the Nation of Islam, which is a work of grotesque psuedoscholarship that simply does not stand up to any kind of scrutiny. I have answered a question on the exact scope of Jewish involvement in the slave trade before here, which I'll reproduce below in quote boxes:

Well, the slave trade was a massive international enterprise; we have evidence of about 35,000 slave voyages that occurred between 1500 and 1866, and though we don't know how many ships were involved because their names often aren't recorded and others are known only by estimation, clearly you need a lot of people and a lot of ships to pull that off. So within that operation, you're of course going to get involvement of Jewish labour and finance; that's an inevitability. On the whole though, Jewish involvement is entirely in line with their representation in the population; there is no disproportionate rate of investment or participation on the part of Jewish people.

For example, from 1715 to 1765, we have evidence of only 377 slaves who were brought from Africa to New York on ships owned by Jewish accounts or financed by Jewish capital; that's less than 1% of the total slaving activity in that period. The largest area of Jewish involvement seems to be in the trade of slaves out of Jamaica onto continental North America, where Jewish investment accounts for 8% of all traffic there before the slave trade is abolished by Britain; but this is an exception rather than a rule, and in other contexts Jewish involvement is virtually non-existent. In importing slaves to Jamaica for instance, only 0.4% of all slaves were transported on Jewish ships. The broad pattern is one of minimal Jewish involvement in the slave trade and especially in the trade coming out of Africa. In the Caribbean, we also generally find - with the exception of Suriname (where there was disproportionately high Jewish investment in sugar) - that when Jewish families and estates own slaves in the colonies themselves, they own fewer slaves than their Christian counterparts.

So if we were to take the Jewish involvement out of the equation, and assume that no-one had filled the gap of Jewish involvement, we would see only the tiniest reduction in the volume of the transatlantic trade. Jewish people simply were not involved in the slave trade in any meaningful way, as either distant financiers or as ship operators; whilst it is important to acknowledge the role of every agent in the slave trade and slavery, as a whole Jewish involvement is quite ancillary to the story.

Eli Faber's book Jews, Slaves, and the Slave Trade: Setting the Record Straight (1999) is a superb rejection of the idea that the Jews were the driving force behind the slave trade, and is essentially a direct response to the nonsense peddled in the 1991 National of Islam book; such is the lack of support for the idea in academic circles that some reviewers were confused as to why Faber had bothered to write a book disproving something that no-one in academia believed in the first place!