I fully expect to have a negative "return on investment" for all the SS taxes I pay (directly through payroll withholding and indirectly in the form of employer paid taxes). Not that it's an "investment" but rather a Ponzi scheme.
The very first SS beneficiary made something $3000 in benefits against about $30 of taxes paid. I'll probably put in around $600-700k over the course of my working life. If you allow for about a 3% annual inflation rate, if I start drawing bennies at 67 (assuming they still exist, and in similar form to now - highly unlikely, but bear with me), I'd get around $4500/month. Assume average life span of 78 and I'd rake in a little under $600k. So, best case I'd see about a 1% loss, perhaps a 14% loss. So I would literally be better off sticking that money as cash under my mattress. Even putting it in a savings account at the local bank at 0.25% APY would put me ahead of SS by $35,000 by the time I retire. A crappy investment that returns 2% (most bond funds will handily beat that) and I'd be ahead by $350,000. Go with a modest/conservative portfolio of mutual funds averaging only 5% and I'd be ahead by almost $1.5million compared to SS. My IRA/401k has averaged about 10% since 2001. With that kind of return, I'd beat SS by a whopping $8.1million.