This paper introduces the Vanguard Research Initiative (VRI), a new panel survey of wealthholders designed to yield high-quality measurements of a large sample of older Americans who arrive at retirement with significant financial assets. The VRI links survey data with a variety of administrative data from Vanguard. The survey features an account-by-account approach to asset measurement and a real-time feedback and correction mechanism that are shown to be highly successful in eliciting accurate measures of wealth. Specifically, the VRI data reflect unbiased and precise estimates of wealth when compared to administrative account data. The VRI sample has characteristics similar to populations meeting analogous wealth and Internet access eligibility conditions in the Health and Retirement Study (HRS) and Survey of Consumer Finances (SCF). To illustrate the value of the VRI, the paper shows that the relationship between wealth and expected retirement date is very different in the VRI than in the HRS and SCF—mainly because those surveys have so few observations where wealth levels are high enough to finance substantial consumption during retirement.