Apple's Piqqem sentiment hits a 15-month low

The "wisdom of crowds" stock-picking site shows a sharp drop over the past three months

In a report timed for release the day before Apple's (AAPL) fiscal Q3 earnings report, Piqqem's Jett Winter charts a sharp decline in investor opinion as measured by his crowd-driven stock selection service.

"In a stunning turn of events," he writes, "sentiment for Apple has dropped 15 points to the lowest level in the past 15 months."

Piqqem is a free website that invites users to make predictions about where a company's stock price is headed using a simple up- and down-arrow rating system. It collects those votes, applies a proprietary algorithm, and displays the collective wisdom of its users in charts and graphs -- something critics say is done even more convincingly by the stock market itself.

On Piqqem's scale of +100 to -100, Apple's current sentiment rating of 34.60 is still considered positive and indicates a quality stock. In fact, Apple has been the top rated equity in Piqqem business and finance category for the past 14 weeks.

But at its peak this year, Apple had a rating of 58 -- 23.4 points higher. Piqqem CEO Winters believes that recent events have taken their toll.

"In analyzing the sentiment line," he writes, "I can identify 2 primary issues. On April 29 Steve Jobs wrote his open letter regarding the state of Flash from Apple's perspective and this corresponded to a 7 point drop in Apple's sentiment. On June 24, Apple released the iPhone 4 which received some bad reviews and this corresponded to another 5 point drop in sentiment.

"As of now, both of these events remain more of a PR issue and Apple's briefing last week about the iPhone 4 should put the company back on track."

Winters notes that the analysts who track Apple still love the stock, with 15 upward EPS revisions in the past 30 days and zero downward. "But even with this momentum," he writes, "something has changed. In the end, only Apple knows their actual results and current sentiment points to the iMac & iPhone giant delivering good results on Tuesday, but there may be clouds forming for the future -- a future where Apple is no longer the darling underdog, but the 700 pound gorilla that everyone else is gunning for."

Below: A chart of Piqqem sentiment in advance of the past 5 quarterly earnings reports.

[Follow Philip Elmer-DeWitt on Twitter @philiped]