Vietnamese banks are planning nearly $7 billion in share sales as the country's fast-growing economy fuels demand for capital, opening a window for foreign investors to expand in the tightly controlled sector. Communist-run Vietnam, which reported growth of nearly 10% in the last quarter, has one of Asia's fastest-growing banking industries but access has been restricted, with cumulative foreign ownership capped at 30%, individual stakes limited to 20% and offshore borrowing subject to strict limits.