What Data Does a Stock Screener Use?
Stock screeners use price and volume data, company fundamentals, valuation ratios, technical indicators, corporate actions, ownership records, and peer data. The quality of a screener depends on how cleanly each layer is sourced and how often it refreshes.
Have you ever wondered why the best stock screener in India can spot a winner when a free tool misses it? The answer is data. Stock screeners use a mix of price data, fundamentals, technicals, corporate actions, and ownership records to filter thousands of stocks down to the handful that match your rules.
Different screeners pull from different sources, refresh at different rates, and apply different cleaning steps. Knowing what feeds the engine helps you trust its output and spot when something is off. Here is the full data stack a serious screener relies on.
1. Price and Volume Data
The foundation layer is exchange-feed data. Every screener starts here. The fields include:
- Open, high, low, close (OHLC) — daily and intraday candles
- Volume traded — share count exchanged in a session
- VWAP — volume-weighted average price for the day
- 52-week high and low — automatically rolled forward each day
- Adjusted close — corrected for splits, bonuses, and dividends
Without adjusted close, your historical price filters return wrong answers after every corporate action. A 1:1 bonus drops the price by half, but the company is the same size. Cheap screeners often skip this step.
2. Company Fundamentals from Quarterly and Annual Filings
The next layer pulls financial statements directly from BSE and NSE filings. Fields include revenue, net profit, operating margin, EBITDA, cash flow, debt, and reserves. Quality screeners pull at least 8 to 10 years of history so trends become visible.
This data refreshes once a quarter, in the days following the company's results announcement. If your screener still shows stale numbers a week after results, find a better one.
3. Valuation Ratios
Valuation ratios are computed on the fly from price and fundamental data. Common ones the screener calculates for you:
- PE ratio — current price divided by trailing earnings per share
- PB ratio — price divided by book value per share
- EV/EBITDA — enterprise value divided by EBITDA
- Price to sales — useful when earnings are negative or volatile
- Dividend yield — annual dividend divided by current price
Two screeners can show different PE values for the same stock. The reason is the earnings window — some use trailing 12 months, others use the last reported full year. Always check which version you are filtering on.
4. Technical Indicators
Most modern screeners now bundle a technical layer for traders. The standard set includes:
- Moving averages — 20, 50, 100, 200-day simple and exponential
- RSI — momentum, usually 14-period
- MACD — trend and momentum combined
- Bollinger Bands — volatility around a moving average
- SuperTrend — trend-following with stop levels
- ADX — trend strength indicator
Technical filters work best when combined with fundamental ones. A stock breaking out on rising volume with a healthy balance sheet is a different signal from a momentum spike on a weak company.
5. Corporate Actions and Events
Corporate action data tracks every event that changes shares outstanding or shareholder value:
- Dividends declared and ex-dates
- Stock splits and bonuses
- Rights issues and offers for sale
- Mergers, demergers, and acquisitions
- Buyback announcements
Screeners use this data to adjust historical prices and compute total shareholder return. They also feed event-based filters like dividend ex-date approaching or recent buyback announced.
6. Ownership and Insider Transactions
Public filings on BSE, NSE, and SEBI portals reveal who owns each stock. The screener tracks:
- Promoter holding — total and pledged percentage
- FII and DII holding — foreign and domestic institutional
- Mutual fund holding — by scheme
- Insider trading data — director and senior management buys and sells
Insider buying clusters often precede strong rallies. Pledged promoter holding above 30 percent is a known red flag. The screener that surfaces these patterns first gives you a real edge. SEBI publishes raw insider transaction data on sebi.gov.in for cross-verification.
7. Industry and Peer Comparison Data
A good screener tags every stock with sector, industry, and sub-industry codes. This lets you compare a company against its real peers, not the whole market. Filters like below sector median PE or above industry average ROE are only meaningful when the tagging is accurate.
Sector classification looks simple but is surprisingly tricky. Reliance Industries shows up under Refining, Telecom, and Retail depending on the screener. Use a tool that lets you see exactly which peer set is applied before drawing any conclusion.
8. Refresh Frequency Matters More Than Anything
The data is only as useful as how recently it was updated. Screeners fall into three buckets:
- Real-time price plus EOD fundamentals — premium tools, prices update tick-by-tick, fundamentals refresh quarterly
- End-of-day everything — the standard for free and mid-tier tools, prices refresh after market close
- Weekly batch — the cheapest tier, often shown in legacy spreadsheet tools, fine for fundamental investors but useless for traders
Pick the tier that matches your style. Long-term investors are well served by EOD data. Active traders need real-time feeds. Match the tool to the timeframe and you avoid both overpaying and being misled by stale numbers.
The Practical Takeaway
Treat screener output as a starting list, not a buy list. Every data field has edge cases, calculation differences, and refresh delays. Use the screener to narrow 5,000 stocks to 20, then read each shortlisted company's annual report before risking real money. The screener saves time. Your judgment closes the loop.
Frequently Asked Questions
- Where does a stock screener get its data from?
- Most Indian stock screeners pull data from BSE and NSE official feeds for prices, from company filings for fundamentals, and from SEBI portals for ownership and insider transaction records.
- How often does stock screener data update?
- Price data updates real-time or end of day depending on the tier. Fundamental data updates within days of quarterly results. Ownership data updates monthly or quarterly based on disclosures.
- Why do two screeners show different PE ratios for the same stock?
- Most often it is the earnings window. Some use trailing 12-month earnings while others use the most recent full-year earnings. The price source can also differ slightly between exchanges.
- Can free stock screeners be trusted for fundamental analysis?
- Yes for basic filters, but always cross-check the headline numbers against the company's annual report. Free tools sometimes lag on adjusted close and corporate actions.
- Do stock screeners include intraday technical signals?
- Premium screeners include real-time technical indicators. Free screeners usually compute technicals on end-of-day data, which is fine for swing traders but not for intraday.