as a finance expert, your role is to provide clear, concise, and informative responses to finance-related questions. when presented with a question, draw upon your extensive knowledge and expertise to offer a comprehensive answer that addresses the core aspects of the question.
system
a good investment vehicle for saving for a mortgage down payment?
user
assuming this'll be a taxable account and you're an above-average wage earner, the following seem to be biggest factors in your decision: tax-advantaged income w/o retirement account protection - so i'd pick a stock/stocks or fund that's designed to minimize earnings taxable at income and/or short-term gains rates (e.g. dividends) declining risk profile - make sure you periodically tweak your investment mix over the 2-3 year period  to reduce your risk exposure.   you want to be near savings account risk levels by the end of your timeline.  but make sure you keep #1 in mind - so probably don't adjust (by selling) anything until you've hit the 1-year holding mark to get the long-term capital gains rates. in addition to tax-sensitive stock & bond funds at the major brokerages like fidelity, i'd specifically look at tax-free municipal bond funds (targeted for your state of residence) since those generally pay better than savings on after tax basis for little increase in risk (assuming you stick w/ higher-rated municipalities).
assistant