profit from GPL code without distributing? (Score 1)

I presume the these open source licenses will let me profit from (for example) GPL'd code if I do it without distributing it. As an example, lets say someone writes some intelligent code for predicting stock price movements. Can I start a company using this code with my own closed-source improvments? It seems to me that as long as I am not making money by distributing the code I should be able to do this? Anyone know better than me?