Equity investors looking to profit from Japan's move away from pacifism might find that easier said than done.

A gauge of defense stocks compiled by Goldman Sachs Group Inc. fell 12 percent this year through last week, trailing the Topix index's 3.3 percent gain even as Prime Minister Shinzo Abe succeeded in passing controversial bills that expand the role of the military. The two Japanese companies that get the most revenue from defense ministry contracts — Mitsubishi Heavy Industries Ltd. and Kawasaki Heavy Industries Ltd. — also make 17 percent of their sales in other parts of Asia, where economic growth is slowing. They've lost $5.4 billion (¥648 billion) in market value this year.

Abe's security push has become his most divisive policy, with thousands protesting in Tokyo and politicians scuffling in the Diet over the bills before they passed on Sept. 19. Still, Goldman Sachs's Kathy Matsui is sticking with her bullish call on the shares, saying they're a good bet over the longer term as regional strains make a bigger role for Japan's military inevitable.