Week 28 Day 4: Value Averaging: DCA's Smarter Cousin

Traditional DCA: invest $500 every month regardless. Value averaging: set a target growth path (say $500/month growth in portfolio value). Month 1: invest $500 (portfolio = $500). Month 2: target = $1,000. If portfolio grew to $550, invest only $450. If portfolio dropped to $400, invest $600. You automatically invest more when prices are cheap and less when prices are expensive.

Value averaging example over 6 months with a target of $500/month growth: Month 1: market flat. Target portfolio: $500. Actual: $0. Invest: $500. Month 2: market up 5%. Target: $1,000. Actual: $525. Invest: $475. Month 3: market down 10%. Target: $1,500. Actual: $900. Invest: $600. Month 4: market up 8%. Target: $2,000. Actual: $1,620. Invest: $380. Month 5: market down 5%. Target: $2,500. Actual: $1,900. Invest: $600. Month 6: market up 12%. Target: $3,000. Actual: $2,800. Invest: $200. Total invested: $2,755. Portfolio value: $3,000. Effective gain: $245 (8.9%). With standard DCA ($500/month x 6 = $3,000 invested), the portfolio would be approximately $2,950 with the same market path. Value averaging produced a better outcome with less capital invested. The downside: you need a cash reserve to handle months where extra investment is required (like after a big drop). Not everyone has that flexibility, which makes traditional DCA more practical for most people.

Value averaging was formalized by Edleson (1988, 1991) as a mechanical investment strategy that explicitly buys more shares at lower prices and fewer at higher prices. Marshall (2000) and Leggio and Lien (2003) compared VA to DCA empirically across multiple markets and time periods. Their findings: VA produces a lower average cost per share than DCA in approximately 90% of scenarios and produces higher internal rates of return in approximately 70% of scenarios. The magnitude of the VA advantage over DCA is approximately 0.5-1.0% annually across most market environments. However, VA has practical limitations: (1) it requires variable cash flows (some months require much larger investments), (2) it may require selling in strong markets (creating taxable events), and (3) it requires ongoing monitoring and calculation (incompatible with full automation). Thorley (1994) showed that VA reduces the standard deviation of the average cost per unit by approximately 20-30% compared to DCA, providing a genuine risk reduction benefit. The theoretical framework: VA implicitly contrarian -- it buys more after price declines and less after price increases. This exploits mean reversion in short-term returns (documented by Poterba and Summers, 1988, at the 1-3 year horizon). For most individual investors, the practical difficulty of VA (variable cash requirements, active management) outweighs the modest performance advantage over DCA. The ideal use case: investors with a large cash reserve who want to deploy it over time with maximum cost efficiency.