DECA Stock Market Game, Western Region. $100,000, ranked on percent return against S&P 500 Growth. Built to maximize return subject to one constraint: never being forced to sell.
“Borrow up to 50% of Total Equity” is an opening buying power rule, not a continuous test. SMG publishes two different formulas. Entry is blocked when (2/3)(stocks + funds + |shorts|) + 0.04×Treasuries exceeds Total Equity. A margin call only arrives when equity falls below 0.30(stocks + funds + |shorts|) + 0.024×Treasuries — and then you get seven days to cure it before the system sells for you.
Those are far apart. This book absorbs a drawdown before a margin call, not the 22.8% an earlier version of this page claimed. That earlier number came from treating the 50% borrow limit as a test applied every day, which is not what the rules say. gross, , borrowed.
Recomputed from the trade ledger on every load. Nothing here is typed in by hand.
| Position | Cost basis | % of gross | Against the $30,000 cap | Buys blocked above |
|---|
The per-security cap is 20% of Total Equity × 1.5. A holding may drift above it on price alone; what the cap blocks is a further buy. The last column is the price at which a further buy would be rejected at the current share count.
Click any day to see what was entered and where the book stood at that close.
Open any row for three sourced reasons, the case against, and the exit.
Verified Sept 8 against the SMG account-summary help and the SIFMA rules. This corrects the central claim of every earlier version of this page.
Every prior version argued that borrowing the full allowance meant an immediate breach on the first down day, because equity falls faster than debt and the allowance shrinks with it. The arithmetic was right. The premise was wrong. SMG does not re-test the 50% borrow limit daily. It applies one formula when you place an order and a different, far looser one to decide whether you get a margin call.
ENTRY Buy Margin Requirement ≤ Total Equity
(2/3)(stocks + funds + |shorts|) + .04×Treas + .10×Muni + .25×Corp
MARGIN CALL Minimum Maintenance > Total Equity
.30(stocks + funds + |shorts|) + .024×Treas + .06×Muni + .15×Corp
then seven days to cure before the system liquidates for you
Survivable drawdown on an all-stock book x = 1 − B / (0.70 G)
For an all-stock book the entry test reduces to gross ≤ 1.5× equity, which is exactly where the “50%” language comes from. The last column shows what the old reading claimed, so the size of the error is visible rather than quietly edited away.
| Gross | Borrowed | Survives, real rule | Old claim | Verdict |
|---|
Every row but this book’s is a hypothetical all-stock portfolio at zero commission. The book’s own row carries the fees paid and the $10,100 Treasury leg — which is why it survives a deeper fall than the smaller all-stock book above it. Bonds barely register on the maintenance test.
Morgan Stanley counts four memory drawdowns since the generative-AI wave began: 15%, 32%, 20%, and the current 17%. A buffer clears of those four. The risk that actually ends this competition was never leverage. It is missing the Oct 23 diversification deadline, which is why all three asset classes go in on day two.
The one thing still unverified: whether the platform also enforces a hard $150,000 gross or $50,000 borrowed ceiling on top of the published formula. DECA's own wording defers to SMG — “up to an aggregate limit, if any, as set forth in The Stock Market Game.” There is a free way to find out. After the Treasury fills, read the account's Buying Power figure: if $10,100 of Treasuries reduced it by roughly $400 the published formula is live, and if it reduced it by the full $10,100 the strict reading is. Until that is known, this book stays close enough to the ceiling that either reading permits it.
Countdowns are from today, computed in your browser.
Read this before trusting the part above.
I cannot tell you this is the best portfolio, and neither can anyone else. Twelve-week returns on individual stocks are close to unpredictable. What separates a good process from a bad one is whether the inputs are true, the rules are obeyed, the reasoning is free of contradiction, and the risk is chosen rather than stumbled into. Those are checkable. “Will it win” is not.
The index-effect error. I used the Sept 21 S&P 100 addition as a reason to buy SanDisk and Dell. The evidence says that effect has largely disappeared since about 2016. SanDisk stayed on three other reasons; Dell was cut entirely, since its case was mostly that plus 7.7% consensus upside. Appealing to a mechanism that used to work is exactly the error worth catching.
An arithmetic error in the table above, found Sept 8. The $120,000 gross row was published as surviving a 40% drawdown. Solving x = 1 − 3B/G at $20,000 borrowed gives 50.0%, and the direct check agrees: after a 50% fall, gross is $60,000, equity is $40,000, and the $20,000 loan is exactly half of it. The other four rows were right. The row understated its own case, but a hand-typed number that disagreed with the stated formula is precisely why the table is now generated from the formula instead.
Stale reference prices, caught before entry on Sept 8. The share counts were sized against Sept 4 closes. Memory rallied hard on Sept 8 — Seagate +8.41%, Western Digital +4.50%, SanDisk +2.23% — so those same counts would have filled at $139,096 gross, 1.391×, with the drawdown buffer at 15.6% instead of 21.7%. That clears one of Morgan Stanley’s four memory drawdowns rather than three, which breaks the argument the book was built on. Worse, Seagate at 32 shares would have sat at 98.2% of the $30,000 cap, so a 1.8% gap on the fill day would have had the order rejected outright. The counts were cut to hold the designed leverage at live prices. Sizing in shares against a stale price is a slower version of the same mistake as typing a computed number into prose.
Most teams will run unlevered, hold ten or more names, and not notice the diversification rule is measured on net cost. Using the borrowing allowance properly, holding few enough positions to move the number, and hitting every deadline raise your finishing percentile without predicting anything. That is the part of this I can stand behind hardest. The stock selection is the part I can stand behind least.
of gross sits in one cycle, which is your equity in memory and storage alone. A 25% move in that theme is a move in your account. That is the deliberate bet, and the presentation should say so plainly rather than dress it up. Outcomes from a 40% loss to a 45% gain over twelve weeks are ordinary here, not extreme.
Rationale, diversification and reflection are 45 of the 100 ICDC presentation points.
One entry a day. Return gets you to ICDC; a record of why you did what you did is what places you once you are there. The record is TRADE-JOURNAL.md in the project folder — the entries below are read from it. The form is a scratchpad that saves to this browser only; write the day’s entry there, then use Copy as Markdown and paste it into the file.