By using TTM, analysts can evaluate the most recent monthly or quarterly data rather than looking at older information that contains full fiscal or calendar year information. TTM charts are less useful for identifying short-term changes and more useful for forecasting.

KEY TAKEAWAYS
Trailing 12-month, or TTM, refers to the past 12 consecutive months of a company’s performance data used for reporting financial figures.
By consistently evaluating trailing 12-month numbers, company financials can be evaluated both internally and externally without regard for the artificiality of fiscal year-end.
TTM allows for a like comparison of a company's performance trajectory that smooths away any inconsistencies.

TTM for Financial Reporting
Companies conducting internal corporate financial planning and analysis have access to detailed and very recent financial data. They use the TTM format to evaluate key performance indicators (KPI), revenue growth, margins, working capital management, and other metrics that may vary seasonally or show temporary volatility.

By keeping a running tab of TTM metrics, a firm's management and stakeholders can understand how the company is doing at any point in time using an apples-to-apples comparison. In other words, by always looking at the previous 12 months, effects such as seasonality or one-time charges can be smoothed out.

TTM for Equity Research
In the context of equity research and valuation, financial results for publicly traded companies are only released on a quarterly basis in securities filings in accordance with generally accepted accounting principles (GAAP).
Securities and Exchange Commission (SEC) filings generally display financial results on a quarterly or year-to-date basis rather than TTM.