Is International Bank of Washington -- the big local financial services firm that has no U.S. bank branches despite its name -- a takeover candidate?

Not likely, given the voting control of IB that rests with its energetic, octogenarian chairman and chief executive, retired Army major general George Olmsted.

But the question has to be raised because of the unusually heavy trading last week in IB stock and the born-again merger fever that has gripped much of America's business community and Wall Street.

Takeover wars, combined with an 8-month-long invasion of record interest rates, have caused the Dow Jones average of 30 industrial stocks on the New York Stock Exchange to plummet 56.37 points in the past two weeks, the longest slide since Richard Nixon was forced to evacuate the White House in 1974. The bond market remains a no-investors' land.

But look at IB: On trading of 1.62 million shares, International Bank's Class A stock was easily the volume leader last week in the nationwide over-the-counter market. IBs class A jumped a dollar a share to a new yearly high of $14.62 1/2, a gain of 7.3 percent for the week and up 17 percent in the past month. For the year to date, IB Class A is a 48 percent gainer. That's pretty smart for a company that has a dividend yield of just 2.7 percent.

IB's performance in 1981 has all the earmarks of a classic takeover in progress. It is quite normal for a stock to be in demand, and for its quoted price to surge, when some merger or acquisition moves are afoot behind the scenes.Moreover, IB is handsomely situated in a variety of industrial and financial lines at home and overseas so that its future looks bright because of protection against downturns in any one sector.

The key fact to keep in mind before rushing out this morning to buy some of this stock, expecting to make it rich on a takeover bid, is that the recently active class A stock is not a terribly important factor in control. As Oplmsted emphasized in an interview yesterday, "the control vote is firmly and rather closely held."

There are about 8 million shares of class A outstanding, which means that about 20 percent of these shares changed hands last week.In terms of IB, however, class A stock is entitled to just one vote per share at stockholder meetings.

Stacked up against class A is the plainly titled common stock, also traded over the counter, but with each share entitled to 10 votes. And who controls the common?

Olmsted himself has 1.65 million common shares, or 36.3 percent of the 4.49 million shares outstanding. The George Olmsted Foundation, an educational and charitable foundation of which Olmsted and his son (Jerauld Olmsted) are directors, owns another block of 478,445 common shares (10 1/2 percent). Counting class A shares that Olmsted also controls, he and the foundation bearing his name control more than 40 percent of all voting shares.

Olmsted, who is something of a legend because of the vigor with which he absolutely runs International Bank every day at age 80, sees "no problem" facing down any takeover attempt but allows as how he "is always alert for these things."

Any merger or acquisition involving IB obviously would have to have Olmsted's backing.

IB officials "are doing the best we can to find out ourselves" why there has been so much interest recently in IB stock, the general stated. Some New York investment firm officials think there has been trading of large blocks of stock between brokers but nothing more significant is known.

What probably is attracting some investors is IB's potential growth at this time and the likelihood of a rebound in earnings. Through subsidiaries and affiliates, IB is engaged in industrial production, property and casualty insurance, life insurance, international banking, finance and leasing, and investments. Earlier this year, IB acquired United Financial Corp. of Virginia, a real estate developer and owner of one-fourth of the stock in United Savings & Loan Association in Northern Virginia.

In its 60th anniversary year, 1980, IB suffered a decline in net income to $13.1 million from $18.5 million the previous year. Industrial companies in which IB has a stake suffered a substantial decline in sales to the automotive industry, there was a 42 percent reduction in sales of standby power generators to the agricultural sector, and property/casualty insurance profits fell by 43 percent. Inflation led to higher interest expenses and strength of the dollar added foreign currency translation losses from international operations.

For the first quarter this year, IB's earnings also declined to $3.6 million from $4.8 million in the 1980 period.

Olmsted said yesterday it is too early to get a clear picture on second-quarter results, noting continuing difficulties in accounting for foreign currency transactions since his company's overseas commercial banking businesses conduct their operations in the currency of their country and since the dollar has been so strong versus other currencies.

For the long run, however, Olmsted is very optimistic about the only major company in America that calls itself a merchant bank. When IB was founded in 1920, it had initial capital of $1 million. As of Dec. 31, capital was $180.6 million, of which $179.6 million of the 60-year growth took place since Olmsted took over the small company at the beginning of 1956. Counting the market value of other investments, IB's net worth today is more than $236 million.

Olmsted, a West Point honors graduate who twice resigned from the Army to pursue business only to return to uniform (his first resignation was in 1923, but he came back in World War II and again during the Korean conflict), prefers a compass to a crystal ball.

In this vein, Olmsted finds the balance of 1981 particularly bright, although there are concerns about international tensions and unrest. He has cited a lessening of the oil supply crisis, indications that the inflation outlook is improving and the conciliatory attitude of current bargaining on labor contracts. The one major problem is the high cost of money.

tOn this point, there were a few rays of sunshine last week that may start peeking out from the clouds starting today. The Federal Reserve Board's policy-setting open market committee met here last week for its midyear review and may have begun some lessening of the money supply constraints that have kept interest rates so high.

There was no evidence of this last week as the key federal funds rate (money traded over night between banks) stayed between 18 percent and 20 percent for the second week, forcing major banks to boost their base lending rate to 20 1/2 percent.