Stocks were mixed in a quiet session on Monday, despite concerns over the financial fallout of Hurricane Harvey as the formerly Category 4 storm batters the Texas coast. The S&P 500 (SNPINDEX: ^GSPC) rose just over a point, and the Dow Jones Industrial Average (DJINDICES: ^DJI) incurred a minuscule decline when all was said and done. Today's stock market Index Percentage Change Point Change Dow (0.02%) (5.27) S&P 500 0.05% 1.18 Data source: Yahoo! Finance. Healthcare stocks rallied as Gilead Sciences announced an $11.9 billion deal to acquire Kite Pharma, helping the Health Care SPDR ETF (NYSEMKT: XLV) climb 0.5% on the day. And retail stocks pulled back after a strong day on Friday, with the SPDR S&P Retail ETF (NYSEMKT: XRT) declining 0.4%. As for individual stocks, Sprouts Farmers Market (NASDAQ: SFM) fell as a new competitive threat began to take shape, and shares of Fitbit (NYSE: FIT) jumped after the wearable fitness device specialist launched multiple new products. Image source: Getty Images. Sprouts withers on competitive worries Shares of organic grocery chain Sprouts Farmers Market fell 9.7% today after Amazon.com began slashing prices at its newly acquired Whole Foods Market locations. To be fair, the move shouldn't have come as a big surprise; Amazon revealed in a press release on Thursday that the purchase would close today, promising that customers would enjoy lower prices on a variety of items. According to Business Insider, however, this morning prices were immediately and drastically slashed on items ranging from whole trade bananas to organic avocados, eggs, fish, butter, apples, and ground beef. Amazon also states there will be "much more to come" going forward -- a promise that many investors understandably view darkly as the e-commerce titan disrupts both traditional grocers and competing organic grocery chains like Sprouts Farmers Market. Sprouts will have an opportunity to appease investors' concerns when its CFO, Brad Lukow, presents at the Goldman Sachs 24th Annual Global Retailing Conference in New York late next week. In the meantime, it's hard to blame the market for bidding down Sprouts stock today. Fitbit's long-awaited premium smartwatch Meanwhile, Fitbit stock climbed as much as 7.3%, then settled to close up 3.6% after the fitness wearable specialist announced a number of compelling new products. Among those products is Fitbit Flyer, a new fitness-oriented set of wireless headphones, and Fitbit Aria 2, an FDA-regulated wireless smart scale. Both will retail for $129.95. But arguably the most exciting product is the new Fitbit Ionic, which represents the company's first true smartwatch and has a starting retail price of $299.95. That's just below the $369 starting price of a similar Series 2 Apple Watch, and well above the $199.95 price of Fitbit's more feature-limited Blaze fitness watch. Fitbit calls the Ionic its "strongest and lightest GPS watch," noting it is waterproof up to 50 meters, and will be loaded with new features and functionality ranging from improved heart rate monitoring to a swim exercise mode, a blood oxygen sensor, Fitbit Pay payments technology, and up to four-plus days of battery life. Ionic will also have access to popular apps including both Pandora and Starbucks, as well as a variety of fitness and health apps from the Fitbit App Gallery. Ionic, Aria 2, and Flyer are available for pre-order today, and will be at retailers globally this fall. If these new devices are well-received by consumers -- with a particular emphasis on the higher-priced Ionic smartwatch -- they could bolster average selling prices, margins, and wearable technology market share for Fitbit going forward. Offer from The Motley Fool: The 10 best stocks to buy nowMotley Fool co-founders Tom and David Gardner have spent more than a decade beating the market. In fact, the newsletter they run, Motley Fool Stock Advisor, has tripled the S&P 500!* Tom and David just revealed their ten top stock picks for investors to buy right now. Click here to get access to the full list! *Stock Advisor returns as of August 1, 2017.Steve Symington has no position in any of the stocks mentioned. The Motley Fool owns shares of and recommends AMZN, AAPL, Fitbit, GILD, P, and SBUX. The Motley Fool has a disclosure policy.