Aces, sorry to hear that but can't say I'm surprised. My advice: let the offer quietly expire, by which I mean do not give HR any response (or if they chase, say you'll use the full offer period to think about it). Get in touch with the interviewer / hiring manager / SE (whoever you feel had the most positive response) and inform them of your offer and how you feel about coming in at that salary, wait for the inevitable "I see... shame, we think you have so much potential, blah blah" speech. Then wait for HR to contact you at which point you politely decline but mention you had a conversation with so-and-so who may have further input into your application.What all this does is give you a potential "second chance" if HR get an earful from an excitable hiring manager or SE for trying to buy a good candidate cheaply. What you should NOT do is worry about it - from your posts you sound like an OK guy and would do well to try your luck with the other Big4's. Happens all the time, HR are always Enemy No. 1 in contract negotiations and play a huge part whether you get a bad offer.