SGX Board Lot Size Singapore: Why Most Stocks Trade in Blocks of 100 Shares
What a board lot is, why SGX standardised it at 100 shares, and how it affects how Singapore investors buy and sell stocks.
Last updated: October 2026
A board lot is the standard trading unit on the Singapore Exchange (SGX) — currently 100 shares for most listed securities — representing the minimum quantity that can be bought or sold through SGX’s regular order book without incurring odd-lot trading complications.
Not financial advice. All figures for educational reference only. Data as at October 2026.
Key Takeaways
- SGX’s standard board lot size has been 100 shares for most listed securities since the exchange moved to this unified standard, replacing the previous system of varying lot sizes (100, 1,000, or more) across different stocks.
- Trading in board lots ensures orders execute through SGX’s main order book at standard bid-ask pricing, while quantities that are not a multiple of 100 shares are classified as ‘odd lots’ and trade through a separate mechanism.
- The 100-share board lot was designed to make investing more accessible to retail investors, lowering the minimum capital needed to buy a single lot of many stocks compared to older, larger lot sizes.
- Board lot size affects practical minimum investment amounts — a stock priced at SGD 30 per share requires at least SGD 3,000 to buy one board lot, a figure investors should factor into portfolio diversification planning.
- Odd lots (quantities below one board lot, or the remainder after buying whole lots) can still be bought and sold on SGX, but typically with wider bid-ask spreads and lower liquidity than board lot trades.
What Is SGX Board Lot Size?
A board lot is the standardised trading unit used on an exchange’s primary order book — the minimum quantity of shares that can be bought or sold at the exchange’s normal quoted bid and ask prices. On the Singapore Exchange, the standard board lot size for the vast majority of listed securities is 100 shares, meaning investors typically buy and sell stocks in multiples of 100.
This standardisation replaced an older system in which different SGX-listed stocks traded in varying lot sizes — some in blocks of 100 shares, others in 1,000-share lots, and a handful in even larger denominations — a system that made it harder for retail investors to compare minimum investment amounts across stocks and complicated order execution. The move to a uniform 100-share board lot across nearly all securities was explicitly aimed at improving accessibility and making the market easier to navigate for retail participants.
Quantities that are not an exact multiple of the board lot size are called “odd lots.” For example, if an investor owns 150 shares of a stock with a 100-share board lot, 100 shares constitute one full board lot while the remaining 50 shares are an odd lot, which typically must be traded through a separate mechanism rather than the main order book.
How Does It Work in Singapore?
For practical investing purposes, the board lot size determines the minimum capital commitment to buy a single lot of a given stock through SGX’s standard order book. A stock trading at SGD 5.00 per share requires at least SGD 500 to buy one board lot (100 shares), while a higher-priced stock at SGD 40.00 per share requires SGD 4,000 for the same one-lot minimum — a meaningful consideration for investors building a diversified portfolio with limited capital.
Most retail brokerage platforms in Singapore default to board lot trading for standard market and limit orders, with odd lot trading available as a separate order type, often through a dedicated odd-lot market maker or matching system, typically at a less favourable price than the prevailing board lot bid-ask spread.
| Share Price | Minimum One-Lot Investment (100 shares) |
|---|---|
| SGD 2.00 | SGD 200 |
| SGD 5.00 | SGD 500 |
| SGD 15.00 | SGD 1,500 |
| SGD 40.00 | SGD 4,000 |
Source: Illustrative calculation based on SGX’s standard 100-share board lot.
Worked Example
A new Singapore investor with SGD 5,000 to deploy wants to build a diversified portfolio across five different SGX-listed blue-chip stocks. If each stock is priced between SGD 10 and SGD 20 per share, one board lot of each would cost between SGD 1,000 and SGD 2,000 — meaning the investor may only be able to afford one lot of two or three stocks rather than spreading evenly across all five, illustrating how board lot sizing directly constrains diversification for smaller portfolios.
To work around this, the investor could consider buying odd lots (fewer than 100 shares) of the higher-priced stocks to achieve broader diversification, accepting the trade-off of typically wider spreads and lower execution priority compared to board lot orders, or use a fractional share or regular savings plan offered by some brokers that pools orders to achieve effective fractional ownership.
Advantages of SGX Board Lot Size
Standardised, predictable trading unit. A uniform board lot size across nearly all SGX stocks simplifies comparing minimum investment amounts and placing orders.
Better liquidity and tighter spreads for board lot trades. Orders in standard board lot quantities benefit from the deepest liquidity and most competitive bid-ask pricing on SGX’s main order book.
Lower barrier than historical larger lot sizes. The 100-share standard is considerably more accessible than the 1,000-share lots that applied to some stocks under the older system.
Clear order execution priority. Board lot orders are matched through SGX’s central limit order book with transparent price-time priority rules.
Widely supported across all brokers. Every SGX-connected brokerage platform supports standard board lot trading without special order types.
Risks and Limitations
Limits diversification for smaller portfolios. Higher-priced stocks can require a meaningful chunk of a small portfolio just to buy one board lot, concentrating risk.
Odd lot trades carry a liquidity penalty. Investors who end up with odd lots — from partial sales, corporate actions, or rights issues — often face wider spreads and less favourable execution than board lot trades.
Can discourage precise position sizing. Investors may be forced to round their intended position size up or down to the nearest board lot, rather than investing an exact desired dollar amount.
Corporate actions can create unwanted odd lots. Rights issues, bonus issues, and share consolidations frequently leave shareholders with awkward odd-lot residual quantities to manage separately.
Not globally standardised. Investors trading across multiple markets need to track different board lot conventions, since not all exchanges use the same 100-share standard SGX applies.
Board Lot Trading vs Odd Lot Trading on SGX
| Feature | Board Lot Trading | Odd Lot Trading |
|---|---|---|
| Standard quantity | Multiples of 100 shares | Any quantity below 100, or the remainder after whole lots |
| Liquidity and spreads | Deepest liquidity, tightest spreads | Thinner liquidity, typically wider spreads |
| Order book | Main SGX central order book | Separate odd lot matching mechanism |
Source: SGX market structure, general trading mechanics.
The Bottom Line
Board lot size is a basic but important mechanic for Singapore investors to understand, since it directly determines the minimum capital needed to trade a given stock and shapes diversification decisions for smaller portfolios. The standard 100-share lot has made SGX more accessible than its older multi-tiered lot size system, though higher-priced stocks can still require meaningful capital for even a single lot.
Frequently Asked Questions
What is the standard board lot size on SGX?
Can I buy fewer than 100 shares on SGX?
Why did SGX standardise board lots at 100 shares?
How does board lot size affect how much money I need to invest?
What happens to leftover shares after a rights issue that aren't a full board lot?
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