A Brooklyn money manager dubbed “the Bernie Madoff of Bay Ridge” was sentenced yesterday to 20 years in prison for defrauding hundreds of investors across the country — with some retirees left virtually penniless.

Philip Barry, 53, operated the sham investment firm out of a Bay Ridge storefront and promised clients guaranteed returns, but instead built a Ponzi scheme that eventually crumbled and costs investors tens of millions of dollars.

Judge Raymond Dearie noted the unusual nature and vast scope of Barry’s 30-year fraud, which targeted family friends, neighbors and others in the Bay Ridge community, but also ensnared investors from across the nation.

“It is a sad story of predatory conduct that is almost unimaginable,” Dearie said in Brooklyn federal court.