Cable and satellite network owner Liberty Global ( LBTYA) is the poster child for a growth-by-acquisition strategy. That at least accounts for part of the reason why the firm has sported such a hefty short interest ratio in 2013. As merger arbitrage traders pile into positions against Liberty, they've ratcheted up the firm's short interest to 15.68. If nothing else, it's a reminder that it doesn't matter why a stock is heavily shorted, only that it is. Right now, it would take more than three weeks of buying pressure at current volume levels for short sellers to exit their positions in Liberty. >>4 Big Stocks on Traders' Radars Liberty owns cable networks, satellite TV operators and phone and Internet providers in more than a dozen countries in Europe and Latin America. Those are high-moat businesses -- because Liberty owns the infrastructure that powers those utilities, the barriers to entry are extremely high for any potential rivals. Liberty's global acquisition spree has yielded a firm that carries considerable debt that's offset by considerable cash flow. That leverage in an environment where rates have slowly been rising doesn't exactly help with LBTYA's short interest. As long as management starts to pare down its appetite, Liberty's financial health isn't at risk. Meanwhile, Liberty's experience operating cable networks in scores of countries gives it unique positioning -- it's able to modernize business models in developing countries and generate substantial cash from its more mature networks. As the firm's networks continue to growth their revenues per subscriber, Liberty's share price should continue growing too.