4:25 PM -- Some days are just plain unlucky. For Cogent Communications Holdings Inc. (Nasdaq: CCOI), that day is August 8. Exactly a year ago to the day, the Ethernet services provider reported earnings and announced that its revenues for the next quarter would fall short of expectations. The stock tanked 22 percent on the news. (See Cogent Suffers Stock Slump.)

Well, Cogent did it again today, warning investors of another sales shortfall for the remainder of the year. (See Cogent Reports Q2.) And once again, Cogent investors responded in kind with a 24 percent sell off. The stock fell $2.72 (24.24 percent) to close at $8.50. That's a new 52 week low.

By all industry accounts, sales of Ethernet-based services around the world are booming. Yet Cogent continues to tumble. At this time last year, some analysts said Cogent was merely due for a correction in its stock price. But that stock has lost 66 percent of its value since then. That's a lot more significant than a correction.— Raymond McConville, Reporter, Light Reading