The Bermuda Stock Exchange saw its second heaviest day of trading ever yesterday when $4.2 million worth of shares changed hands in a single day.

The last time anything near this figure was traded was on June 9, 1998 when $4.79 million changed hands -- mainly due to 208,881 Bank of Butterfield shares being bought and sold.

But yesterday's roaring trade is less easily explained as few of the normally heavily traded bank shares changed hands.

The next highest most recent trading was in December 2000, when $3.3 million changed hands in a single day. Most of the buying and selling on the BSX involves Bank of Bermuda and Bank of Butterfield shares. But it was principally three other shares which changed hands yesterday in surprisingly high volumes. The highest volume of trade was in BF&M 9 percent preferred shares -- 108,038. The shares lost 20 percent of their worth and $2.50 was knocked of the share price, closing at $10.00.

The next highest volume traded was BELCO, where 85,559 shares were sold, and the stock lost 4.6 percent or $1.05 to finish at $22.00.

Then 66,550 shares in Argus Insurance were sold, and the stock lost 2.9 percent or 50 cents to close at $17.00.

But these dramatic exchanges were balanced by a rise in the price of Bank of Bermuda and Bank of Butterfield shares, which closed up 75 cents at $44.75 and up 50 cents at $24.75 respectively. Bank of Butterfield only traded 1,000 shares, and Bank of Bermuda 1,863.

The index closed up overall by 24.11 points or 1.09 percent at 2,240.27 on a volume of 263,143 shares worth a total of $4,1214,335.60.

William Woods, Chief Executive Officer of the BSX said that the high volume in trading was not triggered by a specific event and was hard to comment on. He said that one speculation would be someone was adjusting their portfolio. He said: "There is nothing to suggest what caused the high volume in trading.''