Stock Split
A corporate action that divides each existing share into multiple shares at a lower face value, making the stock more affordable without changing shareholders' proportional ownership.
Definition
A stock split is a corporate action in which a company increases its total number of outstanding shares by issuing additional shares to existing shareholders in proportion to their current holdings, while simultaneously reducing the face value (par value) of each share by the same ratio. In India, companies must obtain shareholder approval and file the requisite documentation with SEBI, NSE, and BSE. The split ratio is expressed as new shares per existing share — for example, a 2-for-1 split means each shareholder receives two shares for every one they hold, with the face value halved. The company's total market capitalisation remains unchanged immediately after the split; only the per-share price and face value change.
Why it matters
Stock splits improve the liquidity and accessibility of a high-priced share. In the Indian market context, a stock trading at ₹5,000 per share may be beyond the reach of many retail investors for meaningful position sizing; after a 5-for-1 split, it trades at ₹1,000, broadening participation. Higher liquidity typically narrows the bid-ask spread, reduces impact cost, and increases daily turnover. For F&O traders, a stock split triggers mandatory exchange adjustments: NSE divides all existing option strike prices by the split ratio and multiplies the lot size by the same ratio, ensuring that every open contract retains its original economic exposure. Traders who held a position before the split wake up to adjusted strikes and a larger lot — the net position value is identical, but the contract specifications change overnight. Understanding this prevents surprise on post-split trading sessions.
Formula
For a split ratio of N-for-1: New Share Price = Old Share Price ÷ N. New Shares Held = Old Shares Held × N. New Face Value = Old Face Value ÷ N. For F&O contracts: New Strike Price = Old Strike Price ÷ N. New Lot Size = Old Lot Size × N. The notional value of one lot (strike × lot size) remains constant across the adjustment.
Example
Suppose a hypothetical company "Epsilon Tech Ltd" trades at ₹4,000 per share with a face value of ₹10 and announces a 4-for-1 stock split effective on a Thursday record date. An investor holding 50 shares worth ₹2,00,000 will wake up on Friday holding 200 shares at an adjusted reference price of ₹1,000 each — still ₹2,00,000 in total. NSE simultaneously adjusts Epsilon Tech's option strikes: a 4,200 CE becomes a 1,050 CE, and the lot size is quadrupled so that each contract still represents the same notional exposure. A trader who held a short 4,200 CE now holds a short 1,050 CE with four times as many contracts in the lot, the premium per share is divided by four, and the total position PnL is unchanged.
Track adjusted strikes after corporate actions
TradePulse automatically reflects post-split strike and lot size adjustments in the live option chain so your analysis stays accurate.