I’ve run the code graphing each variable and the code sets “myequity” to zero which is the problem. here is some fuller code to test for yourself with a market entry of open higher last last close to make it bet in a backtest.

i anyone can figure out how to make it produce a value of “myequity” id be grateful

// Definition of code parameters
DEFPARAM CumulateOrders = True

ONCE bs = 10
//IG SPREAD QUOTES
sp1 = 0.6    //BS <=2000
sp2 =  0.7    //BS <=4000
sp3 = 0.8     //BS <=6000
SP4 = 1.0     //BS <=8000
SP5 = 1.2     //BS >8000
if BS<=2000 then
spread = sp1
endif
if BS>2000 and BS<=4000 then
spread = sp2
endif
if BS>4000 and BS<=6000 then
spread = sp3
endif
if BS>6000 and BS<=8000 then
spread = sp4
endif
if BS>8000 then
spread = sp5
endif

myspread = spread*BS
GRAPH BS
GRAPH MYSPREAD

GRAPH MYCAPITAL
MYCAPITAL = 10000
ONCE MyEquity  = 10000 + STRATEGYPROFIT

//ONCE GAIN = 0
Gain           = StrategyProfit - StrategyProfit[1]

IF Gain <> 0 THEN
MyEquity = MyEquity + Gain - myspread
ENDIF

GRAPH MYEQUITY
tippingpoint=10840*(close*0.05) //AMOUNT OF EQUITY THAT WILL CREATS BETSIZE OVER 10840 £PER POINT
equity = MyEquity*0.5 //BSP PROPORTION OF ACCOUNT WILLING TO PUT AS MARGIN MAX 1
if equity<tippingpoint then
BS = (equity)/(Close *0.05) //IF MARGIN BELOW TIPPING POINT ONLY 5% REQUIRED
else
bs= 10840 + ((equity -(10840*close*0.05)))/(Close *0.15)  //IF MARGIN OVER TIPPING POINT ONLY 15% REQUIRED
endif

if open > close[1] then
buy BS perpoint at market 
endif

Thanks Druby this worked. IG does have variable spreads based on betsize, the values were taken from their spread table on the deal ticket and you are right GraHal that it needs big margin to trigger them. But my backtest on the SPY (S&P500) was turning  £10k into hundreds of millions so over the 2 years and 9 months of the 1min chart data so I needed to factor all variable including variable spread an variable margin for larger bets. This has worked and the actual back test results are more modest and realistic (see screenshot).

Below is the final code that is behaving as expected taking the cost of spread off the profit of each trade and keeping track of the true equity curve which sets the amount of margin available to bet with.

// Definition of code parameters
DEFPARAM CumulateOrders = True
DEFPARAM PRELOADBARS = 5000

//TimeCond = OPENT<OpenTime AND OpenTime<CLOSET
//DayCond = OpenDayOfWeek >= DAY1 AND OpenDayOfWeek <= DAY2

//IG SPREAD QUOTES
sp1 = 0.6    //BS <=2000
sp2 =  0.7    //BS <=4000
sp3 = 0.8     //BS <=6000
SP4 = 1.0     //BS <=8000
SP5 = 1.2     //BS >8000

MYCAPITAL = 10000
Gain           = StrategyProfit - StrategyProfit[1]
if barindex = 0 then
myEquity = MYCAPITAL
else

if abs(countofposition)<=2000 then
spread = sp1
endif
if abs(countofposition)>2000 and BS<=4000 then
spread = sp2
endif
if abs(countofposition)>4000 and BS<=6000 then
spread = sp3
endif
if abs(countofposition)>6000 and BS<=8000 then
spread = sp4
endif
if abs(countofposition)>8000 then
spread = sp5
endif

myspread = spread*abs(countofposition[1])
IF Gain <> 0 THEN
MyEquity = MyEquity + Gain - myspread
ENDIF
endif
equity = MyEquity*BSP //BSP PROPORTION OF ACCOUNT WILLING TO PUT AS MARGIN MAX 1

tippingpoint=10840*(close*0.05) //AMOUNT OF EQUITY THAT WILL CREATS BETSIZE OVER 10840 £PER POINT
 
if equity<tippingpoint then
BS = (equity)/(Close *0.05) //IF MARGIN BELOW TIPPING POINT ONLY 5% REQUIRED
else
bs= 10840 + ((equity -(10840*close*0.05)))/(Close *0.15)  //IF MARGIN OVER TIPPING POINT ONLY 15% REQUIRED
endif

GRAPH BS
GRAPH MYSPREAD
graph STRATEGYPROFIT
GRAPH MYCAPITAL
GRAPH MYEQUITY

Untitled.jpg

The spread table only appears in the IG app when you try to place a trade which is big enough to require variable spread I’ve include a screenshot to demonstrate this

Screenshot_20250210-174815.png