Bitcoin Mayer Multiple DCA: Does Cash Change Results?

A buy rule cannot be judged fairly by comparing only the Bitcoin it bought. The cash it held back belongs in the result too. This comparison freezes one Mayer Multiple rule, contributes the same dollars on the same dates, and separates historical outcomes from evidence that a rule will work in the future.

Bitcoin Mayer Multiple DCA: Does Cash Change Results?

A bitcoin mayer multiple DCA rule did not beat regular monthly Bitcoin purchases in this audit because the rule did not activate. With the default Mayer rule frozen at low 0.8, high 2.4, multipliers 1× / 1× / 0×, bank:true, and $100 monthly contributions, every scheduled purchase in each measured cohort was made at 1×. No purchase was skipped, no cash was banked, and the rule finished exactly the same as flat DCA across all five start dates measured through 2026-10-08.

That is a narrow result, not a general verdict on all smart DCA. An inactive rule cannot show that smart DCA improves returns, and it cannot show that smart DCA harms returns. It can only show that this specific rule, on these specific monthly schedules, did not change the ledger.

The losing example is the 2025 start. Both approaches contributed $2,200 and ended at $2,111.61. That is a negative measured result for that window. The limitation sits beside the result: the Mayer rule did not protect that cohort because, in this run, it behaved exactly like flat DCA.

What was actually tested

This was a calculation audit of one frozen rule, not a search for the best timing system.

The calculation used Bitcoin daily data available through 2026-10-08. Bitcoin’s daily series in BTC DCA Engine begins 2014-09-17, and the site’s data sources page lists the Bitcoin feed, first reading, latest reading, and refresh conventions. For this run, the 200-day Mayer signal was computed from the full BTC snapshot, not from a shortened series beginning on each contribution start date.

The tested schedule and rule were fixed:

• Buy $100 monthly.
• First buy occurs on the start date shown.
• Last buy in every row was 2026-10-01.
• Endpoint valuation was 2026-10-08.
• Flat DCA spends $100 on every scheduled monthly buy.
• The Mayer rule reads: below 0.8 → 1×, between 0.8 and 2.4 inclusive → 1×, above 2.4 → 0×.
• bank:true means skipped money is held as cash and remains part of portfolio value if unspent.
• Unspent cash is counted at face value with zero interest.

The key mechanical point is that the default Mayer rule has only one active difference from flat DCA: it buys 0× when the Mayer Multiple is above 2.4. It does not buy extra below 0.8, because the below-band multiplier is also 1×. It buys normally in the middle band, because that multiplier is 1× too.

So the first question is not “which return was higher?” The first question is “did the rule ever change a scheduled purchase?” In these five monthly cohorts, the answer was no. Because the 0× band did not fire on any scheduled buy in any cohort, the comparison reduces to flat DCA versus the same flat DCA ledger.

Cohort-by-cohort reading

Read each start separately. The equality in one row does not explain the count or balance in another row.

For the 2018-01-01 start, both plans made 106 scheduled buys, contributed $10,600, held 0.6494225826637056 BTC, left $0 cash, and ended at $53,042.46. The Mayer rule did not beat flat DCA; it matched it because it made the same buys.

For the 2021-01-01 start, both plans made 70 scheduled buys, contributed $7,000, held 0.1633970931342207 BTC, left $0 cash, and ended at $13,345.68. Again, this is not evidence of a successful timing rule. It is evidence that the tested rule was inactive for that monthly purchase ledger.

For the 2022-01-01 start, both plans made 58 scheduled buys, contributed $5,800, held 0.13585649087652882 BTC, left $0 cash, and ended at $11,096.26. No cash reserve offset a different coin balance; the coin balance itself was identical.

For the 2024-01-01 start, both plans made 34 scheduled buys, contributed $3,400, held 0.04564518636814462 BTC, left $0 cash, and ended at $3,728.13. This row was positive versus contributions, but the Mayer overlay added nothing to that result.

For the 2025-01-01 start, both plans made 22 scheduled buys, contributed $2,200, held 0.025853386235281627 BTC, left $0 cash, and ended at $2,111.61. This row is the clearest reminder that an inactive smart rule does not create downside protection.

What cash accounting changed — and did not change

Cash accounting was included, but it did not change this result. If the 0× band had fired, bank:true would have kept the skipped $100 in the portfolio as idle cash. That cash would have been counted at face value, with zero interest, rather than disappearing from the comparison.

In this run, the cash column is $0 in every Mayer row. So cash hold matters as a fairness convention, not as a numerical driver of the outcome. The values match because the purchases, units, and cash balances match.

This matters for interpreting smart-DCA claims. A named indicator does not affect a portfolio unless it changes the ledger. If every scheduled buy lands in a 1× band, the indicator may be visible in the rule settings, but the executed plan is still ordinary DCA: same dollars, same dates, same units, same final value.

What this does not prove

This calculation does not prove that all rules-based DCA is useless. It does not test all Mayer thresholds. It does not test different start days within a month, daily or weekly schedules, different multipliers, Fear & Greed, drawdown rules, or any optimized strategy. It also does not test selling rules.

The supplied Smart DCA documentation itself includes broader historical measurements where different rules and starts can help or hurt cost per bitcoin. Those are separate calculations with different assumptions. This article’s result is narrower: the frozen default Mayer rule, with monthly $100 Bitcoin buys, cash hold enabled, five starts, and valuation through 2026-10-08, did not activate and therefore did not change returns.

That narrowness is useful. It prevents the table from being overread. The table is not saying “Mayer always ties DCA.” It is saying “this particular Mayer rule tied DCA here because it made the same purchases.”

Same-close signals are retrospective, not a live trading recipe

BTC DCA Engine’s Smart DCA documentation describes Smart DCA as a Pro overlay that changes how much each scheduled purchase spends. It defines the Mayer Multiple as today’s close divided by the 200-day simple moving average and says the multiple needs a full 200-day window. The same documentation describes the bands, thresholds, multipliers, and bank:true hold convention. The standard scheduling and cash-handling conventions for the simulator are documented in the core engine notes.

For this article, same-close signals and same-close purchases are retrospective illustrations. They are useful for historical arithmetic, but they are not a look-ahead-free executable strategy. A same-day close is not known before that close exists. A live implementation would need an execution timestamp, order timing, fees, spreads, taxes, custody assumptions, and other operational details. None of those are included here.

The rule was not optimized. The default Mayer bands were frozen at 0.8 and 2.4, and the multipliers were frozen at 1 / 1 / 0. No threshold search was run. No fees, taxes, spreads, slippage, or interest model was added. Nothing in the table is a future-performance claim, and a synthetic historical growth result should not be read as a real product, account, or investable return.

Risk, product, and data caveats

Regular DCA can still end below contributed capital over a measured window, and a mild rule may not change that. The 2025 row is the example in this calculation. For a separate historical look at Bitcoin DCA cohorts that spent time below contributed capital, see the related analysis on how long Bitcoin DCA can stay underwater.

Crypto assets also carry risks outside the arithmetic. Investor.gov says crypto assets can vary significantly in characteristics, design, benefits, and risks, and discusses custody and scams. Those account and safety caveats are separate from whether one historical DCA ledger beat another.

BTC DCA Engine is a historical dollar-cost-averaging simulator; see the About page for its operator and process. Matchless Web Studio LLC is not a registered investment adviser, broker-dealer, commodity trading advisor, accountancy firm, or law firm. Nothing here is financial advice.

Smart DCA is described in the supplied documentation as a Pro overlay. Current Pro availability and current MCP/API support should be verified separately before relying on them. Local engine support is not proof that every API or MCP endpoint exposes the same capability for every user or plan.

Synthetic fixed-rate illustrations elsewhere on the site, such as browser-generated CD or 529 examples, are not actual CD or 529 returns, guarantees, tax outcomes, or MCP capabilities.

Reproducible method

To reproduce the arithmetic:

• Use BTC daily closes through 2026-10-08.
• Compute the 200-day Mayer signal from the full BTC snapshot.
• Schedule $100 monthly buys from 2018-01-01, 2021-01-01, 2022-01-01, 2024-01-01, and 2025-01-01.
• Run flat DCA with every scheduled buy spending $100.
• Run the Mayer rule with low 0.8, high 2.4, below 1×, between 1×, above 0×, and bank:true.
• Before comparing returns, verify whether the 0× band changed any scheduled purchase.
• Value BTC holdings on 2026-10-08 and add any remaining cash at face value with zero interest.
• Do not optimize thresholds, add fees or taxes, or treat same-close execution as a live trading recipe.

To test the same idea interactively, open the simulator, use Bitcoin, monthly $100 contributions, and compare flat DCA against the default Mayer Smart DCA rule with cash hold enabled.

FAQ: Did the Mayer rule beat regular DCA here?

No. It matched flat DCA exactly across all five starts because the tested rule did not change any scheduled purchase.

FAQ: Did cash change the answer?

No. Cash was included, but no idle cash remained in any Mayer row.

FAQ: Does this prove smart DCA never works?

No. It only shows that this frozen default Mayer rule, on these monthly schedules through 2026-10-08, did not activate and therefore did not change the purchases or results.