Is Apple Inc.’s iPhone finally reaching its peak? In the past few weeks, a slew of analysts have predicted that sales of Apple’s best-selling product may slump in 2016, based in part on supply chain issues and partly on weaker demand, especially from saturated developed markets.

Apple’s growth is increasingly dependent on demand for iPhones, while iPad tablet sales decline and adoption of the Apple Watch remains modest. Apple predicted in October that it will have another record holiday, with revenue being fueled by demand for the latest iPhones and sales in China.

Some analysts are skeptical. Here’s a breakdown of recent assessments:

• Morgan Stanley lowered its forecast for iPhone unit sales and now estimates a drop of 6 percent in fiscal 2016, according to a Dec. 13 note. The decline is due to higher prices in international markets, excluding China, and maturing smartphone penetration in developed countries. China is the only market with year-over-year iPhone demand growth in the December quarter, according to the report.
• JPMorgan Chase & Co. published a report the same day saying “November sales signal signs of early weakness of iPhone 6S cycle.” The bank lowered its forecast for iPhone units to 75 million to 77 million in the fiscal fourth quarter, down from a previous prediction for 75 million to 80 million units.
• Drexel Hamilton analysts said in a Dec. 8 note that 97 percent of the companies included in a basket of Apple suppliers in Taiwan had reported sales that gave a weaker performance, suggesting that November revenue fell by 6 percent from the previous month and was less than the average 8 percent increase over the past nine years. Drexel predicts iPhone units to grow 4 percent year-over-year in the first quarter of fiscal 2016 and decline by 4 percent in the second quarter.
• Credit Suisse reported in a Dec. 1 note that Apple lowered its component orders in November, suggesting weak demand for the new iPhone 6s. The analysts cite “subdued” iPhone cycle for the next few quarters, but the installed base of iPhone users will grow over time.