Desire to buy the first X of N symbols (a different set of N each day) that reach their limit price triggers intraday, at those prices (no slippage), but without placing N limit orders all at once in advance. Requires code that places orders as price approaches the trigger, possibly cancelling and re-placing them several times depending on price action of this vs. other symbols. Like @ValeryN, I've built software that does this, but would not be comfortable with the potential liability of having other people use it, so it's not currently for sale.Can someone please summarize for me what Sam's problem is
Hmm. but he writes the following, and I think he does not understand that the problem is his position size of 10k, and not the 10 positions he seems to think...Desire to buy the first X of N symbols (a different set of N each day) that reach their limit price triggers intraday, at those prices (no slippage), but without placing N limit orders all at once in advance. Requires code that places orders as price approaches the trigger, possibly cancelling and re-placing them several times depending on price action of this vs. other symbols. Like @ValeryN, I've built software that does this, but would not be comfortable with the potential liability of having other people use it, so it's not currently for sale.
If he takes position size 5k then he can place 20 positions... he even can use all 40 by splitting the avail capital accordingly... simple allocation maths...I want to trade $100,000, with 10 positions at $10,000 each. For tax reasons etc, I don't want to use margin and so I can only send out 10 of the 40 limit orders each day. Most days only 1 or 2 of the limit orders will get hit. If I could use all the 40 limit orders, a lot more than just 1 or 2 orders would get hit and my system would perform a lot better. However, without using margin, Interactive Brokers will stop me from sending out more than 10 orders at $10,000 each with a $100,000 account.
No, I think I understood correctly. Assume it's a strategy that places the limit orders fairly far below yesterday's close, so that on any given day, it would be rare for even as many as 10 to actually reach that price (unless market is crashing). Hence the desire to have more candidates, to increase the chances of getting more than a couple of fills, while also needing to limit total position count to 10 (or whatever fraction is deemed optimal from backtesting) for tail-risk protection.Hmm. but he writes the following, and I think he does not understand that the problem is his position size of 10k, and not the 10 positions he seems to think...If he takes position size 5k then he can place 20 positions... he even can use all 40 by splitting the avail capital accordingly... simple allocations maths...

, b/c 20 * 5k = 100k.As it happens, I'm familiar with the strategy in question. So I'll let you do the re-reading. In particular, see the clause "Most days only 1 or 2 of the limit orders will get hit."
That argument is mathematically irrelevant, b/c the question is about allocating the available capital over 40 orders...As it happens, I'm familiar with the strategy in question. So I'll let you do the re-reading. In particular, see the clause "Most days only 1 or 2 of the limit orders will get hit."
Ie. 2.5k per order he could use and get the most fills, and as he says the most profit the more orders get hit. Of course the current condition would need to be changed so that more orders can get filled instead of the mere 1 or 2...Only if you assume that all the candidates have the same expectancy. In fact, the ones that fill nearer to the open have considerably higher expectancy than the ones that fill later in the day. So there's actually a mathematical advantage to taking fewer but larger positions, i.e., prioritizing the first 10 that reach their limit prices.That argument is mathematically irrelevant
But it depends on the condition, ie. one can increase the fill rate by just changing the condition accordingly.Furthermore, your solution assumes that it's likely for more than 10 to fill on a given day. If we assume (as the original post states) that it is rare to get more than 10 fills even with 40 orders in place, then clearly there's an advantage to using larger than 2.5% size per order.
