Investors are generally most attracted to those new companies distinguished by their strong co-founding team, a balanced "risk/reward" profile (in which high risk due to the untested, disruptive innovations is balanced out by high potential returns) and "scalability" (the likelihood that a startup can expand its operations by serving more markets or more customers). Attractive startups generally have lower "bootstrapping" (self-funding of startups by the founders) costs, higher risk, and higher potential return on investment. Successful startups are typically more scalable than an established business, in the sense that the startup has the potential to grow rapidly with a limited investment of capital, labor or land. Timing has often been the single most important factor for biggest startup successes, while at the same time it's identified to be one of the hardest things to master by many serial entrepreneurs and investors.