3.25% with rebates today from Intarweb Lenders only. Didn't think I'd ever see it but it's certainly here. Even stranger - 15 year fixed in the upper 2's. We finally hit USC's 1.49 10 year T yesterday. Can't wait to see a negative yield 2 year note like the Swiss have. Crazy times.
There isn't a limit in the amount of lender rebate you can be given. It must be spent on things other than principal reductions. You could theoretically refinance at 3.5% and get an impound account paid for, 90 days later kill off the impound account, then refinance again at 3.375%, get the impound account, and so on.
Lenders have both seasoning and benefit to borrower requirements to prevent this kind of "churning". No one wants to book a loan that's in the short run a loser for them only to see it refinanced off the books not long after x number of payments are made. Expect 90 days (3 payments) before you can get rid of an impound account, and most lenders want to see you have 4 to 6 months in your current loan before they will approve a new refinance. From there, the "benefit to borrower" piece comes into play. If you closed at 4.0% and refinance to 3.75% - there's a benefit. If you close at 3.75% and refinance again to 3.75% simply to get a new impound account, that's "churning" and no one's going to take the deal. Some lenders have a percentage of benefit, not just a .125% rate increment requirement in their guidelines.
During the boom, I knew of an accountant in Huntington Beach who refinanced with Countrywide ever 120 days. He had a 1.0% Option ARM that had a great teaser rate and a massive rebate to cover closing costs, while still making the loan officer a rich man for time and effort. Remember in context that this was during the days of a 5.0% 30 fixed and a 4.0% 5/1 ARM market. Eventually as we know today the music stopped and someone was left standing without a chair to sit on. The guy didn't get forclosed on, but for the time that revolving door was going round and round he did very well for himself.
My .02c