Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of Infinera (INFN -0.76%) lost as much as 10% in early trading today and after a slight rebound look to be heading back down to that point again. The market seems to have wanted more than what amounted to a very narrow earnings beat from the company after the close yesterday.

So what: Infinera reported a loss of $0.05 per share on revenue of $128.1 million for the fourth quarter. Its EPS result was a penny better than the $0.06 loss Wall Street expected, and revenue was 14.4% higher year over year, coming in a hair ahead of the $127.4 million analysts sought. For the in-progress first quarter, Infinera expects $115 million to $125 million on the top line and a loss of between $6 million and $11 million, or a loss of $0.05 to $0.09 in EPS terms. Both estimates are in line with analysts, who were looking for $119.5 million in revenue and a $0.07 loss.

Now what: When your stock rises by 50% in three months, then expectations can be understandably high going forward. Nothing in either Infinera's report or its guidance seems particularly impressive, and this seems to be the catalyst behind a loss of investor interest. To sustain a rally, a company needs to continue to offer some reason for optimism, and Infinera just didn't have a reason today.

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