Investors concerned that economic uncertainty will extend into 2008 sent the markets plummeting on the final trading day of the year with the Dow skidding 101 points to 13,265. Nasdaq plunged 22 points to 2652.

On the upside

Towerstream (Nasdaq: TWER) named Jeffrey M. Thompson to the position of chief executive and president.

Vonage Holdings (NYSE: VG) and Nortel Networks (NYSE: NT) settled their patent suit by agreeing to cross license each companies' technology. No payments will be made by either company.

LL&E Royalty Trust (NYSE: LRT) will not issue a trust distribution for January 2008 and announced the termination of the trust.

On the downside

Shares of Research in Motion (Nasdaq: RIMM) dropped as investors took profits.

After more than doubling in 2007, shares of Apple (Nasdaq: AAPL) eased as investors locked in profits.

Falling chip prices along with concerns that sales will fall short of expectations weighed down shares of Nvidia(Nasdaq: NVDA).

In the broad market, declining issues outpaced advancers by a margin of more than 10 to 9 on both the NYSE and Nasdaq. The Russell 2000 which tracks small cap stocks tumbled 6 points to 766.