(AP) -- The New York Stock Exchange's website was apparently hobbled twice Monday, possibly the result of computer attacks as part of the anti-Wall Street protests, according to a company that monitors website response times.

San Mateo-based Keynote Systems Inc. said the NYSE website experienced a one-minute outage around 3:30 p.m. Eastern, then a half-hour outage about two hours later.

But NYSE spokesman Ray Pellecchia said an investigation by the stock exchange showed no disruptions to its website.

The loosely organized Anonymous has threatened an attack on the NYSE. Some protesters have objected to those threats because of the impression a hack would leave about the movement as a whole.

Keynote spokesman Dan Berkowitz said his firm began monitoring the NYSE site Monday after receiving media inquiries about the threats. He said the slowdowns were substantial enough that his firm considered it an outage.

Just because a website is slowed down doesn't mean it was hacked in the typical sense of the word. So-called "" attacks involve bombarding websites with so much bogus traffic that their servers are overwhelmed. An attacker need not ever gain access to the inside of the target's computer systems.

The websites of the NYSE, major banks or government agencies are almost always separate from the computer systems where sensitive transactions are performed.

NYSE's Pellecchia emphasized that trading on the exchange wasn't disrupted, and that the exchange's website is separate from its trading platform.