Stocks in Al Salam, which last week succeeded in its takeover of Bahraini Saudi Bank (BSB), rose by 42.25 percent.
In contrast, Bahraini Saudi Bank was the worst performer on Bahrain’s index, down 40 percent.
After Al Salam, civil and electromechanical contracting firm Nass Corporation was the next best performer, jumping 18.91 percent, followed by Islamic lender Gulf Finance House, up 14.46 percent.
Leisure and recreational facility firm Seef Properties jumped 13.40 percent.
Other poor performers were Al Baraka Banking Group, diving 29.79 percent, and Bank of Bahrain and Kuwait, losing 17.20 percent.
Arabian Business tested the index's performance so far this year by investing an imaginary $100,000 at the beginning of 2009 into each of the companies listed on the BSE.
The Bahrain market is the second-smallest in the Gulf by market capitalisation.
Over the past three months, average daily trading on Bahrain's index was 3.2 million shares.