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how to use all the cumulative equities in the account to buy

2 messages · Gambulator Gambulator

#
Say I am trading SPY and started with 100k. I would like to have my first
trade to buy whatever number of shares SPY I can buy. Then let's say I made
money and my account now has 200k, I want my next trade to use 200k and buy
whatever SPY I can buy and if I lose money then I would use whatever the
leftover is to do the next trade.

I see people talking about using the rebalance function to do that and then
I see people mentioning percentRisk function but I can't quite figure out
how to call these functions properly. Perhaps they are for portfolio with
more than 1 stock and requires asset allocation type of rebalancing.

Is there an out of the box function that would buy using my current equity
? If not, anyone has a custom one that I can use ? After doing some
googling, some people suggest that we can just add the P&L to the initial
capital and figure out the current equity. Is that the way to go ?
#
I did this and it seems to work fine.

osMaxEquity <- function(timestamp, orderqty, portfolio, symbol, ruletype,
...)
{
  updatePortf(portfolio, symbol,
Dates=paste('::',as.Date(timestamp),sep=''))
  Posn = getPosQty(portfolio, symbol, timestamp)
  if (Posn!=0){
   orderqty=0
   return (orderqty)
  }
  cumPL <- sum(getPortfolio(portfolio)$symbols[[symbol]]$posPL$
Net.Trading.PL)
  totalEquity=initEq+cumPL
  closePrice <- as.numeric(Cl(mktdata[timestamp,]))
  orderqty=totalEquity/closePrice
  print(orderqty)
  return(orderqty)
}


I don't know why print does not print anything out though

On Tue, Aug 4, 2015 at 6:26 PM, Gambulator Gambulator <gambulator at gmail.com>
wrote: