Mexco Energy Corporation (AMEX: MXC) shares surged 37.7% to $12.74, on share volume of more than 428,000 shares, compared to a daily average around 2,800.

Yahoo! Inc. (Nasdaq: YHOO) traded Wednesday in 34.6 million shares, nearly doubling its daily average. Prices for YHOO inched back 1.9% to $16.58, amid speculation in some circles that the stock is trading at half of what it should be.

Subaye Inc. (Nasdaq: SBAY) subtracted 12.2% to $7.20 Wednesday, on share volume of nearly 179,000, beating its daily average of about 129,000, a day after announcing it would need more time to file its quarterly results with the SEC.