The bigger, 42mm version of Apple’s new smartwatch is selling way better than the smaller, 38mm version, according to a new research note by analyst Ming-Chi Kuo of KGI Securities. The Apple-watcher blog Appleinsider reported the note earlier Wednesday.

Kuo, who has a reputation for accurate Apple predictions, said big Apple Watches could make up 80% of all watch orders. Kuo speculated that men tended to order the bigger watches—suggesting that men are buying most of the Apple Watches.

The bad news for Apple is that “market demand for Apple Watch may be slowing down” since Apple started taking watch orders in late April, Kuo wrote. Kuo slashed KGI’s forecast for watch orders through September by 20% to 30%, meaning Apple could ship less than 15 million units during that time, according to the blog 9to5Mac. That’s a good bit less than some industry forecasts that Apple could ship 20 to 30 million watches in that stretch, according to 9to5Mac.

Kuo compared the Apple Watch to the iPhone, saying it had “potential” but could take a little while to catch on, according to Appleinsider.

Apple did not immediately respond to a request for comment. It has already said it won’t reveal sales numbers for the Apple Watch. Apple’s share price wasn’t responding—it was flat in early afternoon trading on Wednesday.