The Los Angeles Business Journal’s index of largest local public companies closed up strongly for the week after a drop in the national jobless rate cheered investors.

The weighted LABJ index rose 7 percent to close at 118.68 for the week ended Dec. 2. Gainers outpaced decliners 136 to 31, with 8 companies unchanged.

The biggest gainer was Bank of Manhattan, which soared 56 percent to $3.90. The El Segundo parent of Bank of Manhattan announced a merger with CGB Holdings, the Pasadena holding company of Professional Business Bank.

Physicians Formula Holdings Inc. gained 23 percent to $3.56. The Azuza cosmetics and skin care company made a well-received presentation at an investors conference.

Ixia rose 20 percent to $11.50. The Calabasas computer network products maker benefited from an analyst’s conclusion that flooding in Thailand had not damaged the company’s facilities there as extensively as feared.

One of the largest decliners was Response Genetics Inc., falling 30 percent to $1.05. The Los Angeles life sciences company received a warning letter after failing to maintain Nasdaq’s required minimum market value.

Broadway Financial Corp. droped 21 percent to $1.45. The thrift holding company primarily serving South L.A., received a warning letter from the Nasdaq because it had not yet filed its third-quarter earnings report with the Securities and Exchange Commission.