Overseas investment banks are cautious of Chinese promises to further open its financial sector and skeptical foreigners will be able to access the country's booming stock market anytime soon, the Financial Times reported. China plans to lift a 12-month block on new securities joint ventures this year, but Vice-Premier Wu Yi rebuffed US calls to allow foreign securities firms to set up wholly-owned subsidiaries or raise the ownership caps on foreign investment in Chinese financial institutions. US banks are increasingly frustrated at their inability to play a bigger role in the country's securities, which has seen domestic exchanges soar. On the other hand, Chinese brokerages have profited from the boom and created a powerful domestic lobby against opening the sector to foreigners.