Valuable employees are worth their weight in gold. If she's worth it to your company, pay her what she's asking, and make it clear that you expect your pound of flesh (and hopefully you have the mechanisms and metrics to measure that). If she's coming through an agency and you're liable for fees, tell them you'll pay half now and the bal in 6 months, provided she's still with you. I have some respect for people who have a record of performance and can negotiate their own salary ... but I'm suspicious of those who play one offer against the other - they should just say what they require and negotiate for that. Orange flag raised. Depending on the person I'd offer sightly less and promise to review in 6 months based on performance.