Chris Lau, Kapitall: Nuance and Apple are popular tech stocks for Carl Icahn. But should you follow his lead? Carl Icahn boosted his holding in Nuance Communications (NUAN) between December 6 – 10, adding to his already sizeable stake in the voice command tech stock. Overall, shares in Nuance are down 36% in 2013, but recently bounced from a bottom. [Read more from Kapitall: Mexico Liberalizes Oil Fields: How Energy Stocks Could React] Profits at Nuance in the last year are not steady, due to rising costs and higher R&D expenses. With Carl Icahn now holding 19.2% in the stock, should investors be expecting him to shake up the company in the weeks ahead? Icahn bought an additional 1.38 million shares, and he now holds nearly one-fifth in the company. The large position stirred rumors that the activist could push Apple (AAPL) to buy out Nuance. But this rumor does not sound likely to play out: Nuance has a market capitalization of $4.43 billion, while Apple likes to make small acquisitions. Click on the interactive chart to see NUAN and APPL stock prices over time. Very recently, for example, Apple bought PrimeSense for $350 million. PrimeSense develops chips that give machines the capability to observe a scene in three dimensions. Competitor Microsoft (MSFT) is a license holder of the technology. Risks of following Carl Icahn Nuance has about $1.2 billion in convertible debt. And new entrants are joining the voice recognition market, making it more critical for Nuance to expand rapidly into more markets. Anyone using Google (GOOG) Voice will notice how strong the service is. In the enterprise market, Nuance recognizes the value of voice dictation in the medical field. Nuance is making it easier to transcribe voice dictation for electronic medical records.