I think I read this on a telnet server, many years ago - so it may be quite obscure.
The story centers around a programmer, who's happily married to a doctor, and his friend who is a "hacker/Private Investigator". This friend uses his spare time to blackmail sysadmins to give him access to datacenters, and uses this access to plant software agents that collect data. This data is used "Machine Learning" style, to determine obscure connections between datasets. Through this 'hobby' he discovers a hedgefund, called 'Pentecostal Jihad', that consistently beats the market in everything they touch. He suspects insider trading, and tries to get a congresswoman (or senator) to start an investigation. As the story progresses, he becomes convinced that 'Pentecostal Jihad' is indeed an AI, and is using its powers to 'increase entropy' in society. Meaning that random, disrupting events occur more and more often, which in the end leads to something akin to the end of western civilisation. The programmer becomes jobless, then homeless, and in the end muses about 'knowing that something more advanced than humans has spoken'.
Sounds crazy - I know :) But it was really good, and I want to read it again! Please help me find it, if you can.