5) Market Mechanics
What is Bid and Ask
Every time you buy or sell a stock, two prices are at play: the bid and the ask. Understanding both can save you from overpaying or underselling. This is a fundamental concept you must grasp before pressing that order button.
Definition
The bid is the highest price a buyer is willing to pay. The ask (or offer) is the lowest price a seller will accept. The difference between bid and ask is called the spread — the tighter the spread, the more liquid the stock.
Simple Explanation (Analogy)
Imagine haggling at Pasar Tanah Abang. You want a shirt and offer Rp50,000 (your bid). The seller says 'minimum Rp65,000' (the ask). If you go up to Rp60,000 and the seller comes down to Rp60,000, a deal happens. That Rp15,000 gap is the spread. In the stock market, this process happens thousands of times per second.
Indonesian Stock Example
Blue chip stocks like BBRI usually have a very tight spread, just Rp5-25. But illiquid third-tier stocks can have spreads of Rp50-100 or more. That's why buying illiquid stocks can put you at an immediate loss from the spread alone — you buy at the ask of Rp500, but can only sell at the bid of Rp450.
How to Use
- Always check the spread before ordering. If the spread is too wide (more than 1-2% of the stock price), be cautious — you're already losing before you start.
- Use limit orders at the bid price when buying for a better price; don't always default to market orders.
- Watch how the bid-ask changes after big news — spreads usually widen during market volatility.
Common Mistakes
- Always using market orders without thinking, automatically buying at the ask (the more expensive price).
- Ignoring spreads on small-cap stocks, ending up stuck because the bid is far below the purchase price.
- Confusing the last traded price with bid and ask — the last price is just a record of the previous transaction, not the price you can get now.
FAQ
Why do GOTO's bid and ask move so fast?
GOTO is among the highest-volume stocks. Many active traders and algorithms constantly place and cancel orders, making the bid-ask move very rapidly. This is actually a good thing because the spread tends to be tight and liquidity is high.
Is the spread always fixed?
No. The spread fluctuates throughout the day. It's usually tightest during peak trading hours (around 9:30-11:00 and 13:30-15:00). At session opens and closes, spreads can widen due to uncertainty.