If you define altruism as any action which when taken improves another's survival, and threatens/risks your own, then it is clearly not. This is how Dawkin's defined it in the Selfish Gene, and I think that there's something to it. Further, it's not to your benefit, but to your genes (but that is another topic).
What this means is that you can do many actions for others that appear to be charitable, but are actually selfish. This is what you're getting at, but it's only half of the picture. A person may do something that appears absolutely selfish, but the degree of risk to themselves makes it an ultimately altruistic act given that it benefits the survival of someone/something else.
There are plenty of actions that a person can take that reward others and do not benefit themselves.