I am planning to invite my in-laws. As per immihelp.com, it makes sense to ask my wife to sponsor my in-laws as it proves "closer ties". The only concern is that my wife's income level (she is currently on a part-time job) is not strong. I, however, am on a job transition and hence can not readily produce current employment letter. The question is whether level of income matter in order to sponsor (and hence produce I-134) or is just the bank balance that matter? Any thoughts appreciated!