On this page 7 sections
A one-minute candle can tell you four things: where price opened, how high it went, how low it went and where it closed.
What it cannot tell you is how the market travelled between those four points.
And sometimes, that missing path is the entire story.
Imagine a one-minute candle with:
- Open: 1.1000
- High: 1.1010
- Low: 1.0990
- Close: 1.1005
There are many possible ways the market could have produced that candle.
It might have moved:
1.1000 → 1.1010 → 1.0990 → 1.1005
Or:
1.1000 → 1.0990 → 1.1010 → 1.1005
Same candle. Completely different sequence.
For a chart reader looking at the candle after it has closed, that distinction may not matter.
For a trading algorithm with a stop loss, trailing stop, pending order or intrabar signal, it can mean the difference between a winning trade, a losing trade and no trade at all.
That is where tick data enters the picture.
A tick is a market update
A tick is an individual market-data update.
Depending on the market and data source, it may contain information such as:
- timestamp,
- Bid price,
- Ask price,
- Last traded price,
- volume,
- flags describing what changed.
MetaTrader 5's native MqlTick structure, for example, can hold Bid, Ask, Last, volume and a timestamp with millisecond precision.
A tick also does not necessarily mean that every field changed.
The Bid can change while the Ask remains the same. The Ask can move without the Bid. On exchange-traded instruments, a Last trade or volume update may occur.
That makes tick history much richer than a simple list of prices.
Bid and Ask matter
This is especially important in Forex and CFD testing.
A chart may visually focus on one price, often Bid, while actual trading involves both sides of the market.
The difference between them is the spread.
If the market is:
Bid 1.1000 / Ask 1.1002
a strategy buying immediately is not entering at 1.1000. The Ask side matters.
The same applies when a position is later closed.
This is why a tick dataset containing genuine Bid and Ask history can tell you something a simple OHLC file cannot: what the tradable market looked like at that moment.
Tick data and tick volume are not the same thing
The terms are easy to confuse.
Tick data describes individual market updates.
Tick volume usually counts how many tick events occurred during a bar.
A one-minute candle with a tick volume of 150 therefore does not give you those 150 ticks. It only tells you how many were recorded for that bar.
The sequence itself is still missing.
Why traders use tick data
Tick data becomes particularly important when a strategy depends on what happens inside a candle.
Examples include:
- scalping,
- very tight stop losses,
- trailing stops,
- stop and limit orders,
- spread-sensitive entries,
- tick-driven indicators,
- intrabar breakouts,
- high-frequency event logic,
- strategies that can enter and exit within the same bar.
For a strategy that makes one decision at the open of every daily candle, tick-level history may be unnecessary during early research.
For a strategy that reacts to a two-second price excursion, it can be essential.
The right question is therefore not:
“Is tick data always better?”
It is:
“Does my strategy depend on information that candles have already discarded?”
Candles are compressed market history
Candles are incredibly useful.
But they are compression.
An M1 bar can summarize hundreds or thousands of market updates into four prices plus some additional fields.
That compression makes charts manageable and research faster.
The cost is that information disappears.
Once a sequence of ticks has been reduced to OHLC, the exact order of events inside that candle cannot be reconstructed with certainty.
A testing platform can generate a plausible path.
It cannot recover a historical sequence that was never stored.
Tick data does not automatically make a backtest realistic
There is an important warning here.
Real tick history improves the description of historical price movement, but a backtest can still contain unrealistic assumptions about:
- latency,
- slippage,
- commissions,
- order execution,
- liquidity,
- broker rules,
- symbol specification,
- time zone,
- trading sessions.
High-resolution data is one component of a realistic simulation.
It is not a substitute for a realistic testing environment.
The practical takeaway
Think of market data as different levels of resolution.
A daily candle gives you a broad picture.
A one-minute candle gives you much more detail.
Tick history exposes the stream of market updates from which those candles were formed.
The closer your strategy operates to the microstructure of the market, the more likely that lost detail matters.
And that leads to the next question:
How different can a backtest become when we replace one-minute candles with actual ticks?
PRIMARY SOURCES