SAN FRANCISCO, JULY 8 -- BankAmerica Corp., busily wooing Japanese banks for help in rebuilding its sagging capital, has hit on a new plan to raise more money at home by offering current stockholders a 5 percent discount on purchases of common stock.

Analysts praised the move as a prudent way for BankAmerica to boost its capital by $100 million or more. But one stockholder said he is unlikely to invest more money in a banking company that has already suspended his dividend for 18 months.

"Well, I don't think it's anything sensational," said Emil Rossi of Booneville, Calif., whose owns 1,000 shares of BankAmerica stock. "They're tossing {out} a piece of something that's just not a deal. They're just trying to get some more money, because they need it."

The discount offer, called the shareholder investment plan, will take effect July 20, and is outlined in a prospectus being mailed to BankAmerica's stockholders. It replaces BankAmerica's shareholder reinvestment plan, which was canceled June 8.

The discount offer gives BankAmerica's shareholders the opportunity to buy up to $10,000 worth of BankAmerica stock each month at a discounted price.

The price will be equal to 95 percent of the average of the high and low market price that is recorded during the first five trading days following the 20th of each month, according to BankAmerica spokesman Art Miller.

Shareholders who do not take during the first five trading days following the 20th of each month, according to BankAmerica spokesman Art Miller.

Shareholders who do not take advantage of the plan will "continue to receive cash dividends," according to the prospectus, which does not mention that BankAmerica suspended its dividend on common stock in the first quarter of 1986.

Miller called the plan an "opportunity for shareholders" to boost their holdings in a "convenient and economical" way.

"It's a way of selling common stock on the installment plan," said Donald Crowley, senior vice president for Keefe, Bruyette & Woods in San Francisco. "Rather than coming to the market with, say, $100 million worth of common equity, B of A could possibly raise that much in a year, through this plan."

BankAmerica stock gained 37.5 cents yesterday to close at $11.62 1/2 in trading on the New York Stock Exchange.

BankAmerica has already gone to U.S. financial markets earlier this year with $100 million in 10-year notes, but was forced to pay a hefty yield of 11 percent to entice investors.

Discount offerings of stock have become a popular tool for banks intent on quickly raising capital. That is a goal at BankAmerica, whose capital was eroded in June by a $1.1 billion addition to loan loss reserves to cover further reverses in the Third World.

"The company obviously needs capital, particularly in light of these {less developed country} decisions," said Charles Peabody, vice president for equities research at Drexel Burnham Lambert Inc. in New York.

However, Peabody warned that the discount offer could reduce BankAmerica's earnings per share -- 34 cents a share in the first quarter -- by increasing the amount of shares in the market.

It could also encourage volatility in the price of the stock at the end of the month, when the offer takes effect, if arbitrageurs scurry to buy the discount BankAmerica stock as a hedge against other investments.