Michael!

I hear you in fact when I wrote my first algo i had the same problem with standing cash and guess what.... I too ecide to fill it with bonds!
Here is the link to it if you are interested. Basically there are many ways to solve this problem, I think the approach of using the order_target_percent() method to be really nice as it also allows you to control your leverage should you ever decide that's needed. With that method you can explicitly target your portfolio's holding to whatever security you want.

order_target_percent(stock, 0.75)  
order_target_percent(bond, 0.25)  

Welcome Michael.

As James pointed out you can use the order_target_percent function.

See attached backtest.

If this were live trading, would it be better to sell the bond prior to buying the security in the MA1 < MA2 case? I'm curious if the buy would fail on an account without margin based on which orders are submitted.

Thanks for the help,

I noticed it makes trades every day to maintain the allocation, is there a way to limit the trades to just when the MAs cross?

Yeah you could do it so only when there is a cross trades are being made. Consider setting somesort of boolean flag whose state you change upon a cross over.

def initialize(context):  
    context.MA1_above_MA2 = False

def handle_data(context, data):  
    MA1 = data[context.stock].mavg(5)  
    MA2 = data[context.stock].mavg(9)

    current_mavg_indicator = MA1 > MA2

    if not  context.MA1_above_MA2 and current_mavg_indicator:  
        order_target_percent(context.stock, .40)  
        order_target_percent(context.bond, .25)  
        order_target_percent(context.ibond, .30)  
        order_target_percent(context.gold, .15)  
    elif context.MA1_above_MA2 and not  current_mavg_indicator:  
        order_target_percent(context.stock, 1)  
        order_target_percent(context.bond, 0)  
        order_target_percent(context.ibond, 0)  
        order_target_percent(context.gold, 0)

    context.MA1_above_MA2 = current_mavg_indicator  

Try that out let me know if I made any mistakes and I'll edit the reply.