FRANKFURT — Nearly half of Germany’s gold reserves are held in a vault at the Federal Reserve Bank of New York — billions of dollars worth of postwar geopolitical history squirreled away for safe keeping below the streets of Lower Manhattan.

Now the German central bank wants to make a big withdrawal — 300 tons in all.

On Wednesday, the Bundesbank said that it would begin moving some of the reserves, the second-largest stock in the world after that of the United States. The goal is to house more than 50 percent of German gold in Bundesbank vaults in Frankfurt by 2020, up from a little less than a third today, the bank said.

Citing security reasons, Carl-Ludwig Thiele, a member of the Bundesbank, declined to say how the transfer would be accomplished or to estimate the cost. But he said the Bundesbank had plenty of experience moving large sums of money.

During the cold war, West Germany followed a policy of storing its gold as far west as possible in case of a Soviet invasion. While that worry is gone, there is still an argument for keeping some gold in financial centers like New York and London. It remains the one currency that is accepted everywhere. In the event of a currency crisis, the gold could be quickly deployed in financial markets to help restore confidence.