NS&T Bankshare's offer to buy control of Security National Bank expired yesterday with no word from NS&T about whether the tender offer was successful.

Security National President Thomas J. Schaefer said yesterday that, based on shareholders' responses to letters urging them to hold onto their stock, he believes the offer will not succeed.

"We've been getting numerous calls over the past three or four weeks from people saying they're in agreement with the board," said Schaeffer, who added that more than 75 percent of the shareholders had indicated they were opposing the takeover and proposed merger.

NS&T Chairman Joseph Riley said the bank would have no comment yesterday on how many shares were tendered. NS&T's officials will meet with stockholders today in a special meeting.

NS&T offered on Aug. 4 to buy up to 100 percent of Security National's shares at $62, a price Security said was too low in light of the smaller bank's prospects for profitability. Security National officials have since urged shareholders in two letters to reject the NS&T offers.

Even before the NS&T offer, Security had announced on July 22 that in an effort to ward off a hostile takeover it would merge with the smaller Washington Bank. That announcement followed Security National's rejection of a bid by James Madison Ltd., parent company of Madison National Bank, to pay $60 a share for up to 44 percent of Security's stock.

There were reports of heavy trading in Security National stock late last week as some investors apparently opted to take $62 from the market rather than wait to get their money from NS&T if the offer succeeds or take the chance that it would not. NS&T is not obligated to buy any shares unless at least 40 percent of the stock is tendered.

Nearly 8,000 shares traded last week, according to Lewis Sosnowik of M. Lang & Co. Normal volume in the stock is 200 to 300 shares a month, he said. "Cash speaks with a loud thunder," Sosnowik commented. He also said that he believes shareholders will reject an offer that will result in Security's disappearance.

No quotation for Security National has appeared for two weeks in a listing of area stocks published in Sunday's Washington Post. On Sept. 4, Lang & Co. informed the National Association of Securities Dealers Inc. that, for now, it would not be making a market in Security stock because it was overwhelmed with sell orders.