I am a pure mathematician teaching a 2-2 load at a state research university in the United States. I know that many of my colleagues in applied math, engineering, and the laboratory sciences are able to buyout much of their teaching as long as they are successful in obtaining grant funding.
This doesn't seem to be the case in pure mathematics, however. In the US, most external funding for pure math comes from the NSF or the NSA. A program officer at the NSA explained to me that they don't allow buyouts, even in lieu of requesting summer salary. I e-mailed the same question to a program officer at the NSF, and my e-mail was not returned. I also asked my chair if I could pay for a buy-out (down to 2-1) from my own money, and he said no -- only grants or startup money are acceptable for this purpose.
I am curious -- are pure mathematicians ever able to secure course buy-outs, other than in their first few years (when this seems common)? Are there any funding agencies whose funding I might compete for that allow this? Alternatively, are buyouts from salary acceptable in other departments?