GoPro is tanking

GoPro shares fell more than 4% to start the week.

In an article last weekend, Barron's magazine wrote that the company's stock could fall to $25 per share. Based on Friday's closing price of $35.15, that's a 29% decline.

The stock is already down 44% year-to-date.

Alexander Eule at Barron's wrote that the big downside for GoPro is competition. Eule calls the company's point-of-view cameras a "one-product wonder" and compares them to BlackBerry smartphones that were once all the rage.

The article notes that Apple is a looming threat; when it emerged in January that Apple obtained a patent for a camera that could compete with GoPro's cameras, shares fell 12%.

Also, Chinese manufacturer Xiaomi announced a 16 megapixel camera, similar to and much cheaper than GoPro cameras.

The threat from other brands is something analysts have been warning about as they watched the stock price fall.

Before the market open on Monday, the stock declined to as low as $33.65 per share.

Shares are down 2% from the IPO last June.