How It Trades
- Each bar, compute the 20-bar simple moving average of the close and its Bollinger Bands two standard deviations above and below.
- Buy when the close drops below the lower band: price is unusually cheap relative to its own recent range, and stretched moves tend to snap back.
- Hold through the bounce and sell only when the close rises above the upper band, capturing the full ride from one edge of the channel to the other.
Example Strategy
Pine Script
Paste it into TradingView’s Pine Editor to run these rules on any chart.
//@version=6
// Bollinger Band To Band — sort.finance. Fills at the signal bar's close, 0.02% fee a side,
// whole account per trade, as the backtest. History and indicator warm-up
// differ from the site's, so expect close to the same trades, not identical.
strategy("Bollinger Band To Band", overlay=true,
initial_capital=100, default_qty_type=strategy.percent_of_equity,
default_qty_value=100, commission_type=strategy.commission.percent,
commission_value=0.02, process_orders_on_close=true, pyramiding=0)
// The bar the current position opened on, and the bar the last one closed on.
var int entryBar = na
var int exitBar = -1
// ── Signals ──────────────────────────────────────────────────────────────
[middle, upper, lower] = ta.bb(close, 20, 2)
enterNow = close[1] >= lower[1] and close < lower
exitNow = close[1] <= upper[1] and close > upper
// ── Orders ───────────────────────────────────────────────────────────────
// Open on the first bar the entry holds while flat; close on the first
// later bar the exit holds; never reopen on the bar a position closed.
inTrade = strategy.position_size != 0
if inTrade and bar_index > entryBar and exitNow
strategy.close("Long")
exitBar := bar_index
else if not inTrade and bar_index > exitBar and enterNow
strategy.entry("Long", strategy.long)
entryBar := bar_index
// ── Drawing ──────────────────────────────────────────────────────────────
plot(upper, "Upper Band", color=#8a92a0)
plot(middle, "Middle Band", color=#4d8dff)
plot(lower, "Lower Band", color=#8a92a0)