In a New York Times op-ed which has been receiving deserved criticism from other quarters concerning other matters (e.g., here and here), Ta-Nehisi Coates ("The Good, Racist People") repeated one of those establishment press-induced "everybody knows" mantras which doesn't stand up to scrutiny after considering the available evidence: "New York is a city, like most in America, that bears the scars of redlining, blockbusting and urban renewal. The ghost of those policies haunts us in a wealth gap between blacks and whites that has actually gotten worse over the past 20 years." In Coates's fevered mind, it's largely due to racism.
In national context, the white-black wealth gap in the two decades since 1993 is not yet known, but in 2005, the 15th of the past 20 years for which information is available (1991-2010), it stayed the same. The multiple only went up significantly when the housing bubble burst and the recession took hold.