The margin requirements for a collar are as follows:  

Initial below $3.00/share: 100% of the stock + the cost of the put option and no requirement on the short call  

Initial $3.00/share and above: 50% of the stock + the cost of the put option and no requirement on the short call  

Maintenance below $3.00/share and the call option is in, or out of, the money: lesser of 10% of the strike price of the put option + 100% of the out of the money amount on the put option or 100% of the call option strike price  

Maintenance above $3.00/share and the call option is in, or out of, the money: lesser of 10% of the strike price of the put option + 100% of the out of the money amount on the put option or 25% of the call option strike price