HONG KONG — In what would be a drastic liberalization of China’s huge but still cloistered capital markets, the country’s top securities regulator said Monday that foreign investment could be allowed to rise as much as tenfold.

Citing the still-nascent levels of overseas participation in domestic stock markets — despite recent actions more than doubling the amount of money that foreign funds can invest there — Guo Shuqing, the regulator, hinted 2013 could bring sweeping new measures to open financial markets in China.