Earnings estimates are generally consolidated estimates which are averages of the estimates given by a number of market analysts.
Companies give their own guidance on earnings estimations, and they will have their feet held to the fire, so to speak, if they are consistently off with their guidance, but most people will, rightly, give more weight to the consolidated estimates of outside experts.
Earnings estimates on a publicly traded company will come from an array of industry analysts, and are normally consolidated into a single average estimate or range. The range might or average will certainly affect the trading prices of the stock, but not as much as adjustments to estimates will.
Company-issued earnings guidance may support the industry analysts, but investors will be wise to listen to the outside analysts over the company. Companies do have a lot of pressure to be honest with their estimates, because losing the trust of investors can be a very bad thing, but there is still too much of an inherent conflict of interest to take the company’s estimation over the estimates of analysts.
Earnings are the proverbial “bottom line” for companies and their investors. Earnings per share and earnings growth will be part of the reports that come out of the estimations.