Top fluc, short for top fluctuation, pays a winning bet at the highest price recorded for its runner during a betting window, not at the price on offer when you bet. With illustrative prices, a runner that opens at $6.00, peaks at $7.50 and starts at $5.00 pays $7.50 on terms that cover that whole line. A $10 winning bet returns $75.00 instead of the $50.00 a starting price bet would.
Two parts of the operator's terms set the figure: whose price history counts, and the window it is read over. Neither is the same everywhere, so one bet of this kind can pay differently at two bookmakers.
How the top fluc price is set
Three questions settle any bet paid this way:
| Question | What the terms decide | Why it changes the payout |
|---|---|---|
| Whose prices count? | The price source, such as an official price service | Two sources can record different highs for one runner |
| Over what window? | When recording starts and when it stops | A high outside the window does not count |
| For which bets? | Bet types, meetings, stake sizes and when betting on it stops | A bet outside these is not paid at the high |
Even the official versions differ. Racing NSW states that since May 2017 its NSW Official Price service has produced the official flucs for NSW TAB race meetings, and with them the SP and the top fluc (checked October 2026). The service works from the prices of the larger licensed wagering operators, corporate bookmakers and TAB fixed odds among them.
Western Australia's Rules of Wagering 2005 define the wager differently for WA bookmakers, in the version in force from 7 October 2025. It is a win wager at the highest on-course bookmakers' odds for the runner (rule 3(1)). Those odds are determined by a pricing information body that Racing and Wagering Western Australia (RWWA) selects. One name, two definitions of whose prices count.
The window is the operator's own choice. Check when it opens, when it closes, when the operator stops taking these bets, and whether prices recorded before your bet was placed count towards it.
Worked: opens $6.00, peaks $7.50, starts $5.00
Example: An illustrative fluc line for one runner, not a real race. Implied chance = 1 / price.
| Time before the advertised start | Price | Implied chance |
|---|---|---|
| About 5 hours, market opens | $6.00 | 16.7% |
| 4 hours | $6.50 | 15.4% |
| 2 hours, the high | $7.50 | 13.3% |
| 1 hour | $6.80 | 14.7% |
| 30 minutes | $6.00 | 16.7% |
| 10 minutes | $5.40 | 18.5% |
| The start, its SP | $5.00 | 20.0% |
What a $10 bet returns if the runner wins, paid four ways:
| How the bet is paid | Price | $10 returns |
|---|---|---|
| Fixed price taken when the market opened | $6.00 | 10 x 6.00 = $60.00 |
| Highest price, window from the open to 10 minutes before the start | $7.50 | 10 x 7.50 = $75.00 |
| Highest price, window covering the final hour only | $6.80 | 10 x 6.80 = $68.00 |
| Starting price | $5.00 | 10 x 5.00 = $50.00 |
The market firmed from a 13.3% chance at the high to 20.0% at the start, and the bet was paid the price from before it did. Under a final-hour window the same bet pays $7.00 less, because the high came two hours out. Both windows are illustrative: yours is in your bookmaker's terms.
Risk: Betting involves risk. The higher price only applies if the runner wins, and a beaten runner costs the whole stake whatever its price history did. See responsible gambling for limits and support.
Why operators limit it to some meetings and stakes
Paying every winner at its high is expensive, because the highs of a field come from different moments. With the runner above and four illustrative others in the same race:
| Runner | SP | 1 / SP | High in the window | 1 / high |
|---|---|---|---|---|
| Runner 1 | $2.20 | 45.5% | $2.60 | 38.5% |
| Runner 2 | $3.40 | 29.4% | $4.00 | 25.0% |
| Runner 3, from the worked example | $5.00 | 20.0% | $7.50 | 13.3% |
| Runner 4 | $8.00 | 12.5% | $9.50 | 10.5% |
| Runner 5 | $13.00 | 7.7% | $17.00 | 5.9% |
| Total | 115.1% | 93.2% |
The starting prices add up to 115.1%, a market with the bookmakers' margin built in. The highs add up to 93.2%, below 100%. If an operator took bets across that field in line with those highs, it would pay out $100 for every $93.20 it took, whichever runner won. No punter can stake that way, because the highs are known only once the window closes, but the sum shows the operator's cost.
That cost is why the terms limit the product. The levers to look for:
- the meetings, codes or countries it covers;
- a maximum stake or payout at the high;
- a betting cut-off before the start;
- win bets only;
- the operator's right to decline or cut a bet.
Risk: Betting involves risk. A field whose highs add up to under 100% is a cost the operator carries across every runner, not a return you can lock in on one bet, and a beaten runner still costs the whole stake. See responsible gambling for limits and support.
Top fluc vs taking the current fixed price
You choose at one moment inside the window. The fixed price is what you get now. The bet's price is at least the highest the window has recorded so far, if your terms count prices from before your bet, and it can still rise. Two illustrative cases, each 45 minutes before the start, under illustrative terms whose window runs from the market open to 10 minutes before the start and counts all of it:
| Case A: the high is already in | Case B: the runner firms from here | |
|---|---|---|
| Official price now | $6.40 | $6.00 |
| Highest official price so far in the window | $7.50 | $6.00 |
| Your bookmaker's fixed price now | $6.50 | $6.40 |
| Official prices for the rest of the window | Falling to $5.40 | Falling to $5.20 |
| Paid at | $7.50 | $6.00 |
| $10 at that price returns | $75.00 | $60.00 |
| $10 at the fixed price returns | $65.00 | $64.00 |
| Better on a winner | The high, by $10.00 | Fixed, by $4.00 |
Two rules come out of those cases. When the terms count the whole window and its high so far already beats the fixed price you can take, the product cannot pay less than that high on a winner, deductions aside. When your bookmaker's fixed price sits above the highest official price recorded so far in the window, the product only wins if the official price later climbs above your fixed price inside the window. A stake above a cap, a bet after the cut-off or a meeting the terms leave out takes the choice away.
Starting price betting covers the other figure set after you bet, the official price at the jump.
Risk: Betting involves risk. A better price on a winner does nothing for the losers, which cost the full stake either way, and the terms can cap or decline the bet. See responsible gambling for limits and support.
A payout rule, not the flucs you read
Horse racing flucs are a record of where a runner's price went. Top fluc is a settlement rule that reads one number off one record, so the highest figure you saw is not always the one you are paid. With illustrative prices, three ways the two part company:
| What you saw | What the bet pays | Why |
|---|---|---|
| One bookmaker's own high of $8.00 | The official high of $7.50 | Terms that read an official source ignore that bookmaker's line |
| $9.00 on race morning, before the window opened | The highest price after it opened | The early price sat outside the window |
| A drift to $7.80 after the window closed | $7.50 | The high is read only inside the window |
Before you count on a figure, find it in the source your terms name and inside the window.
Scratchings, dead heats and a missing price
- Late scratching. After a late scratching, the race-day Stewards set a cents-in-the-dollar cut for successful fixed-odds bets placed before it, and the high may date from before it too, when the field was bigger. Whether and how your bookmaker cuts a bet paid this way is in its terms. Take an illustrative 9c deduction on the $7.50 high: on the face-value reading of Racing NSW's BR 14(4), $10 pays $75.00 x (1 - 0.09) = $68.25. Taken from the winnings only, it pays $10 + $65.00 x 0.91 = $69.15. Scratching deductions covers both readings.
- Dead heat for first. On course in NSW, a dead heat for first pays one-half of the ticket's face value (BR 16 of Racing NSW's Rules of Betting). WA's Rules of Wagering split the return by how many runners dead-heat (rule 58). On the $7.50 high, a two-way dead heat pays $75.00 / 2 = $37.50. Online bookmakers set their own terms, and dead heat rules has the detail.
- No official price. For WA bookmakers, if the pricing information body sets no price for the runner before the start, the odds are based on the middle win dividend paid by an Australian totalisator (rule 51A(2)). Other bookmakers name their own fallback.
Five top fluc mistakes and what they cost
The figures are the illustrative ones used earlier.
- Counting a high outside the window. Under a final-hour window the worked runner pays $6.80, so $10 returns $68.00, not the $75.00 the $7.50 high suggested: $7.00 less.
- Taking the product over a higher fixed price on a firming runner. Case B paid $60.00 against $64.00 at the fixed price: $4.00 less.
- Staking past a cap. Under illustrative terms that pay the high on the first $100 of a stake and SP on the rest, $200 on the worked runner returns 100 x 7.50 + 100 x 5.00 = $1,250. At $7.50 throughout it would be $1,500: $250 less.
- Assuming every bet type qualifies. WA's rule book defines the wager as a win wager, so check whether your terms extend it to place or each way bets.
- Leaving the deduction out. Expecting $75.00 and receiving $68.25 after the illustrative 9c deduction on the face-value reading ($69.15 if it comes off the winnings only).
Reading the market before you choose
Choosing between a fixed price now and a high recorded later starts with knowing where your bookmaker's price sits. B337's Terminal puts prices from 40+ bookmakers across racing and sports in columns, next to Betfair back and lay, with price history (flucs) and closing lines, the last prices before the jump. Those are the prices bookmakers publish, not an official price service, so settle any question about your payout against the source your terms name.
Because the board reads prices on a repeating cycle rather than tick by tick, a price can be newer at the bookmaker than on screen, so check it in your account first. A free account opens a limited view of the Terminal with live odds. Horse racing betting maps the other ways a race can pay, best of the best among them. Bookmaker names are trade marks of their owners. B337 is not affiliated with them. Betfair is a trade mark of its owner, and B337 is not affiliated with it.
Risk: Betting involves risk. A bookmaker price sitting above the rest of the market says nothing about whether the runner will win, and it can be cut before your bet lands. See responsible gambling for limits and support.