A developer’s plan to move the New Jersey Nets to Downtown Brooklyn has gotten a boost from Wall Street.

Investors quickly bought out $511 million in tax-free bonds that went on sale yesterday to pay for part of the much-delayed project.

Nets principal owner Bruce Ratner says the strong sales are a sign that investors have confidence in the project.

Ratner and his company hope to finish the arena by 2011. They eventually plan to add apartment towers and office buildings to the site.