iPhone 5, Mac concerns lead to lowered Apple estimates by Philip Elmer-DeWitt @FortuneMagazine October 16, 2012, 1:02 PM EST E-mail Tweet Facebook Google Plus Linkedin Share icons FORTUNE — When Apple AAPL is about to release its quarterly earnings we usually see analysts scrambling to raise their estimates so as not to get sandbagged by numbers that were better than they could have imagined. But with the company set to report fiscal Q4 results next Thursday Oct. 25, we’re seeing the opposite. Three analysts trimmed their estimates on Monday and we could see more of that before the week is done. Excerpts from the notes we’ve received so far: William Blair’s Anil Doradla: Tweaking Near Term Estimates Based on iPhone 5 Supply Constraints. “Since unveiling the iPhone 5 last month, consumers have faced significant delays in receiving the phone. In our opinion, Apple’s inability to keep up with demand is being amplified by its aggressive global launch schedule and the company reducing its exposure to its traditional partner, Samsung. Checks across North American retail stores to understand the impacts of the delays highlight two interesting trends: first, the majority of customers seeking the new iPhone have not switched brands, and second, pricing cuts lead to better‐than‐expected sales of the iPhone 4 model. Based on the recent delays, we are reducing our iPhone estimates for the September quarter [to 26.5 million from 33 million].” Gabelli’s Hendi Susanto: We are revising our prior estimates to account for iPhone 5 launch, very weak global PC shipment data, and our expectations. “We are projecting revenue of $37.8 billion (34% yoy growth) and EPS of $9.10 per share… We cut our Mac shipment estimate to 4.7 million units from 5.3 million (10% decline in Desktops and 1% decrease in Portables from last year)… We are cutting our iPhone shipment estimate considering the later than expected launch date, early ramp up of iPhone 5 production and potential supply constraints. We are now expecting 29.9 million vs. 32.1 million units.” Morgan Stanley’s Katy Huberty: All eyes on iPhone with a wide range of potential outcomes. “Backend loaded in-cell display production ramp and shipments en route or in the channel are major swing factors influencing reported C3Q iPhone units. We conservatively model 25M iPhones, 15M iPads, 4.8M Macs and 5.7M iPods for the quarter. We lowered our Mac shipments from 5.2M as preliminary IDC data point to weak PC demand and slow Mac sales ahead of new product launches. This results in revenue and EPS of $33.9B and $8.29 – both below consensus. iPhone units and gross margin are more likely to surprise positively than negatively, in our view.” Note: Huberty’s revenue estimate of $33.9 billion is lower any other analyst we’ve polled this quarter.