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Stock Split & Bonus Shares Explained: What Happens to Your Shares

When a company announces a stock split or bonus issue, your portfolio changes overnight — but does your wealth? This guide explains stock splits (1:2, 1:5, 1:10), bonus shares, rights issues, the math behind each, tax implications, and recent Indian examples from Tata Motors, IRFC, and Infosys.

8 min readPublished 27 May 2026

“Company X announces 1:5 stock split!” — You see this headline and check your demat account. Your 100 shares have become 500 shares. The price has dropped from ₹1,000 to ₹200. Are you richer? Poorer? Neither. But the market often reacts as if something fundamental has changed. This guide explains what actually happens during stock splits, bonus issues, and rights issues — and what it means for your portfolio and taxes.

Stock split: more shares, same value

What is a stock split?

A stock split increases the number of shares outstanding by dividing each existing share into multiple shares, while proportionally reducing the face value. The total value of your holding does not change.

Think of it like exchanging a ₹500 note for five ₹100 notes. You have more pieces of paper but the same amount of money.

The math

Split ratioOld face valueNew face value100 shares becomePrice adjustment
1:2 (2-for-1)₹10₹5200 sharesPrice halves
1:5 (5-for-1)₹10₹2500 sharesPrice drops to 1/5th
1:10 (10-for-1)₹10₹11,000 sharesPrice drops to 1/10th

Example: You hold 100 shares of Company X at ₹2,000 each (total value: ₹2,00,000). The company announces a 1:5 split. After the split, you hold 500 shares at ₹400 each. Total value: still ₹2,00,000. Your cost basis per share adjusts from ₹2,000 to ₹400.

Why companies split stocks

Record date and ex-date

When a company announces a split, two dates matter:

T+1 settlement impact: Since India moved to T+1 settlement, you must buy the stock at least 1 trading day before the record date to be recorded as a shareholder. Buying on the record date itself means settlement happens the next day — too late.

Recent Indian stock split examples

Bonus shares: free shares from reserves

What are bonus shares?

A bonus issue is when a company gives existing shareholders additional shares for free, funded from the company's accumulated reserves (retained earnings or share premium account). Unlike a split, the face value does NOT change — but the price adjusts proportionally.

The math

Bonus ratio100 shares becomePrice adjustmentFace value
1:1 (1 bonus for every 1 held)200 sharesPrice halvesUnchanged
1:2 (1 bonus for every 2 held)150 sharesPrice drops to 2/3Unchanged
2:1 (2 bonus for every 1 held)300 sharesPrice drops to 1/3Unchanged
3:1 (3 bonus for every 1 held)400 sharesPrice drops to 1/4Unchanged

Example: Infosys announces a 1:1 bonus. You hold 100 shares at ₹1,800 each (value: ₹1,80,000). After bonus, you hold 200 shares at ₹900 each. Value: still ₹1,80,000. But Infosys has converted ₹1,800 crore from reserves to share capital on its balance sheet.

Why companies issue bonus shares

Dilution: does bonus issue dilute your ownership?

No. Every shareholder gets bonus shares in proportion to their existing holding. If you owned 1% of the company before the bonus, you own 1% after. Your ownership percentage is unchanged. The total number of shares outstanding increases, but your proportionate claim on earnings and assets is identical.

This is fundamentally different from a fresh equity issuance (like an IPO or FPO), where new investors come in and dilute existing shareholders.

Recent Indian bonus issue examples

Stock split vs bonus issue vs rights issue

ParameterStock splitBonus issueRights issue
What changesFace value reduces, shares multiplyMore shares issued from reserves, face value unchangedNew shares offered at a discount, investor pays money
Cost to investor₹0₹0You pay the rights issue price per share
Company receives cashNoNoYes (that's the point — to raise capital)
Balance sheet impactNone (only face value changes)Reserves decrease, share capital increasesCash increases, share capital increases
Ownership dilutionNoNoNo (if you subscribe). Yes (if you don't).
What if you ignore itAutomatic — shares split in your dematAutomatic — bonus shares credited to dematYour ownership gets diluted. You can sell the rights entitlement on the exchange.

Rights issue: the one that costs money

Unlike splits and bonuses, a rights issue requires you to pay for additional shares — typically at a 20-40% discount to market price. The company is raising fresh capital from existing shareholders.

Key rule: If you don't want to subscribe to the rights issue, sell your Rights Entitlement (RE) on the exchange before the deadline. REs trade like regular shares for a limited period. If you ignore the rights issue entirely, your ownership gets diluted AND you lose the value of the RE.

Recent example: Reliance Industries rights issue (2020) — 1:15 at ₹1,257/share when market price was ~₹1,600. Investors who subscribed locked in a 21% discount. Those who ignored it lost ~₹23 per existing share in dilution value.

Tax implications of corporate actions

Stock split tax treatment

Bonus share tax treatment

Tax trap example: You bought 100 shares at ₹500 in 2022. Company issues 1:1 bonus in May 2026. You now have 200 shares. If you sell all 200 shares at ₹300 in August 2026:

Rights issue tax treatment

What to do when your company announces a corporate action

  1. Read the announcement on BSE/NSE. Check the exact ratio, record date, and purpose (especially for rights issues).
  2. For splits and bonuses: No action needed. Shares will automatically adjust in your demat. Verify the credit after record date + 2-3 business days.
  3. For rights issues: Calculate whether subscribing makes sense. Compare rights price to current market price. If you don't want to subscribe, SELL the RE on the exchange before it expires.
  4. Update your cost basis records. Your broker should adjust cost in the holdings tab, but verify manually. Tax computation requires accurate cost basis.
  5. Don't trade based on split/bonus announcements alone. The price adjusts proportionally. There's no guaranteed arbitrage. The stock may rally post-announcement (sentiment-driven) or may not.

The psychological trap

Retail investors often treat splits and bonuses as “good news” and rush to buy. Studies show a short-term positive price reaction around announcement dates (2-5% abnormal returns in the Indian market). But this is largely driven by retail sentiment, not fundamental change.

A ₹200 stock post-split is not “cheaper” than the ₹1,000 stock pre-split. The company's earnings, cash flows, and competitive position are identical. If you wouldn't buy at ₹1,000 pre-split on fundamentals, you shouldn't buy at ₹200 post-split either.

The correct response to a split/bonus announcement: note it, update your records, and continue your investment thesis evaluation as if nothing happened. Because economically, nothing did.

Use the capital gains calculator to model the tax impact of selling split or bonus shares, and check the capital gains tax guide for the full FY26 framework.

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