First Security Corp.'s directors have declared a three-for-two split of the company's common stock.

The split comes in the form of a 50 percent stock dividend through which shareholders will receive one additional share for each two shares they hold.The board of the Salt Lake-based financial services company also voted to increase the regular quarterly cash dividend to 23 cents per share, a 7.8 percent increase, after adjusting for the stock split, from 21.33 cents per share. That adjusted figure was established in July 1989, when directors raised the dividend from 20 cents.

The action was announced Monday afternoon at First Security's annual meeting of shareholders at the Utah Power & Light Co. auditorium downtown.

"Both the stock split and the increased cash dividends reflect the continued growth of earnings of the corporation and the economic vitality of the marketplace served by First Security banks," said Chairman Spencer F. Eccles.

"Moreover, this will increase the total shares outstanding and cause the stock to be more attractively priced for the small investor in the retail market."

Both the 50 percent stock dividend and the higher quarterly cash dividend are payable June 3 to shareholders of record May 17. The increased cash dividend represents 92 cents per share annually. The company said that, at a market price adjusted for the split, the annual dividend yield would be approximately 4.2 percent.

During his remarks at the annual meeting, Eccles outlined for shareholders the corporation's goals for 1991 and the years ahead. They are:

- Be the "primary economic catalyst" of the state and region.

- Be "solidly profitable with a representative stock price."

- Earn 15 percent or more return on equity.

- Earn 1 percent or more on assets.

- Maintain a strong capital position.

- Continue providing "the highest quality financial services to our customers."

Eccles noted that the company had an aggressive year in acquisitions during 1990, adding 24 full-service commercial banking offices and 21 automated teller machines to its network. As for future acquisitions, he told shareholders:

"At this time, we are not assured of an equally large window of opportunity for possible future deposit purchases from the government-owned Resolution Trust Corporation. We continue, however, to look for additional acquisitions within our market region that would enhance market share and improve earnings."

The current board of 19 directors, 10 officers and five honorary directors were re-elected during the annual meeting. Morgan J. Evans, formerly executive vice president and chief financial officer, was elected president and chief administrative officer, to be effective Wednesday, succeeding Robert T. Heiner who retired effective Tuesday.

First Security Corp.'s 1990 and first quarter 1991 earnings and other financials were reported earlier this month on these pages.