Buick Grand National/GNX
Flagged undervalued because inventory -1%, and sell-through 97%.
What It's Actually Worth
Blended value of a standard 37 yr, 32k mi example, ~$48.0K now. The green line weighs confirmed auction sales most heavily (the amber dots — what cars actually hammered for), blends in fast-selling "just-missed" listings, and lightly smooths out month-to-month composition noise.
Did our model work? 73% direction calls right
Each faint amber line is a forecast we would have made at that point in the past (12-mo horizon), drawn against what actually happened (blue). Over 110 scored forecasts: 73% got the direction right, median value error ±35%.
Walk-forward: each ghost uses only data available at that date — no hindsight. Data-backed market intelligence, not a guaranteed prediction. Figures are modeled estimates from asking prices, sold comps, and public economic indicators; they can be wrong. Not financial advice.
Auction Scorecard gavel in range 9 in 10
We replayed 191 past auctions in this market — predicting each hammer price from market data before the sale (no hindsight). Typical miss: ±19%; the gavel landed inside our predicted range 9 in 10 of the time.
| Sold | Car | Our range | Hammer | |
|---|---|---|---|---|
| 2026-09-17 | 1987 | $22.2K–$105K | $46.3K | ✓ |
| 2026-09-17 | 1987 · 41k mi | $25.6K–$80.5K | $43.3K | ✓ |
| 2026-09-09 | 1987 · 24k mi | $28.4K–$89.3K | $70.0K | ✓ |
| 2026-08-21 | 1987 · 72k mi | $21.4K–$67.3K | $28.5K | ✓ |
| 2026-07-24 | 1987 · 20k mi | $28.3K–$89.0K | $68.2K | ✓ |
| 2026-07-23 | 1984 · 73k mi | $20.7K–$65.0K | $20.9K | ✓ |
| 2026-07-14 | 1987 · 26k mi | $26.9K–$84.6K | $45.5K | ✓ |
| 2026-07-10 | 1986 · 4k mi | $36.1K–$114K | $80.5K | ✓ |
Live now — calling it before the gavel
We're currently tracking 8 open auctions in this market. Here's our predicted hammer range for each — check back after they close.
| Closes | Car | Source | Our predicted range |
|---|---|---|---|
| open | 1986 · 0k mi | hemmings | $36.9K–$169K ($78.9K) |
| open | 1986 · 0k mi | hemmings | $36.7K–$168K ($78.7K) |
| open | 1986 · 56k mi | classic | $19.2K–$88.7K ($41.3K) |
| open | 1987 | classic | $21.5K–$91.0K ($44.2K) |
| open | 1987 · 15k mi | hemmings | $23.3K–$98.8K ($48.0K) |
| open | 1987 · 7k mi | classic | $27.1K–$115K ($55.9K) |
| open | 1986 · 7k mi | classic | $27.1K–$115K ($55.9K) |
| open | 1987 · 50k mi | classic | $19.5K–$82.7K ($40.2K) |
No-lookahead: predictions are made before each auction closes; the scorecard grades confirmed sold auctions only (no-sales excluded). A modeled estimate, not a guarantee. Data-backed market intelligence, not a guaranteed prediction. Figures are modeled estimates from asking prices, sold comps, and public economic indicators; they can be wrong. Not financial advice.
Where We Think It's Headed
Probability and range, not a single number. Wider = less certain (not bigger gains).
| Horizon | Direction | Probability | Confidence | Past accuracy |
|---|---|---|---|---|
| 6 mo | UP | 53% | Low | 66% |
| 12 mo | DOWN | 45% | Low | 73% |
| 24 mo | FLAT | 50% | Low | 89% |
Data-backed market intelligence, not a guaranteed prediction. Figures are modeled estimates from asking prices, sold comps, and public economic indicators; they can be wrong. Not financial advice.
Crystal Ball — What Leading Indicators Signal
Distinct from the trend forecast above: this blends all 8 leading indicators (each at its own lead time, de-duplicated so correlated ones don't double-count) into one signal. Leading indicators are collectively signaling higher over the next ~12 months (low conviction — 24% of weighted drivers agree), driven mainly by Gold (futures) and Nonfarm Payrolls (jobs), though Gold (futures) points the other way.
Are the indicators agreeing?
Each bar is one driver's current push; longer = more weight. All one side = high conviction; split = low.
If You’d Bought in 2012
$100K invested 2012-01 → today (14.7 yrs), this car vs where else you could've put the money. Rebased to 100 at the start; the dashed line is inflation (break-even).
What This Market Follows
Specialty-car prices don't move in a vacuum. These economic indicators have historically led this market — tap one to see it shifted forward by its lead time, overlaid on the value line.
CPI (All Urban Consumers) leads by about 23 months (moves with this market, correlation 0.95). Shown shifted forward 23 months so its turns line up with the market's.
Why We Think This
Current Inventory Snapshot
Comparable Markets
| Market | Undervaluation | Appreciation | Liquidity |
|---|---|---|---|
| Chevrolet Camaro Z28 (5th Gen) | 53 | 36 | 56 |
| Ford Mustang Fox Body SVT Cobra | 49 | 41 | 29 |
| Plymouth Barracuda | 32 | 82 | 37 |
| Plymouth Barracuda 'Cuda | 33 | 86 | 63 |
| Chevrolet Camaro (2nd Generation, 1970-1981) SS | 42 | 42 | 37 |
| Chevrolet Camaro (2nd Generation, 1970-1981) Z28 | 59 | 36 | 52 |
| Chevrolet Camaro 3rd Gen | 53 | 51 | 46 |
| Chevrolet Camaro 3rd Gen IROC-Z | 50 | 47 | 50 |
Recent Signals & Alerts
- vin returned lower VIN relisted $-26,000 vs prior
- vin returned higher VIN relisted +$7,000 vs prior
- price jump Median asking moved sharply (z=-65.0)
- vin returned higher VIN relisted +$25,900 vs prior
- price jump Median asking moved sharply (z=-15.0)
- vin returned higher VIN relisted +$7,000 vs prior
Data-backed market intelligence, not a guaranteed prediction. Figures are modeled estimates from asking prices, sold comps, and public economic indicators; they can be wrong. Not financial advice.