At Microsoft, the two big sellers were Steven Sinofsky, president of the Windows division, and Kurt Delbene, president of the Office division. Combined, these Microsoft insiders dumped 106,348 shares, or $3 million worth of stock, at an average price of $28.26. Most of that selling was just the exercising of options from these two key Microsoft insiders. From a technical standpoint, Microsoft has a ton of overhead resistance at around $29 and $31 a share. Market players should watch the stock closely here to see if it can break out above those prices and start a new bullish uptrend. As of now, the insiders selling at Microsoft, which has been very heavy for the past few months, doesn't seem to be affecting the stock negatively. Microsoft is one of the top tech holdings of David Tepper, as of the most recent reporting period, and according to Jake Lynch, it's one of 10 Dow stocks likely to boost dividends this year. One company outside of tech that saw some large insider selling from a key corporate executive was Tyco International ( TYC), a diversified company that provides security products and services, fire protection and detection products and services, valves and controls, and other industrial products. The entire insider selling at Tyco was done by Edward D. Breen, the chairman and CEO of the company. Breen sold 153,743 shares, or $6.9 million worth of stock, at an average share price of $44.68. Most of the selling by Breen was the exercising of options, but it did take his entire position down by around 7%. Shares of Tyco look technically strong, with the stock currently trading just one point off if its 52-week high of $45.37. My take here is that Breen is just taking advantage of the strength in the overall stock market to lock in some profits. His selling when compared to his entire holdings wasn't at a level that would raise a red flag. Major holders of Tyco include Maverick Capital, and it's one of TheStreet Ratings' top-rated industrial conglomerate stocks. To see more stocks with heavy insider selling, including Family Dollar Stores ( FDO), Monsanto ( MON) and Range Resources ( RRC), check out the Top 20 S&P Stocks With Big Insider Selling portfolio on Stockpickr. -- Written by Roberto Pedone in Winderemere, Fla.