GOOD
New Year resolutions wave + NFL playoffs lead-in. Operators reset annual marketing budgets.
Solid month to claim. Headline values strong; structure terms not unusually punitive.
Original Research 13 operators tracked 28 months of data Updated 2026-04-30
The Promo Erosion Calendar:
When US Sportsbook Bonuses Are Best & Worst
Across 13 major US sportsbook operators tracked from January 2024 through April 2026, welcome bonuses follow a predictable seasonal cycle. The same operator often runs an offer in June worth less than half its September peak. This calendar surfaces the pattern with monthly Best Offer Scores, the three months bettors should claim, and the three to avoid.
Sep · Oct · Mar Top 3 months to claim
Jun · May · Jul Bottom 3 months
40 pts Peak-to-trough gap
bet365 Most consistent operator
Executive Summary
Five findings from the data
01
The same operator's June offer is worth ~57% of its September offer
Across the 13-operator panel, the average annual score range is 40 points (peak 93.4 → trough 53.3). For most operators that translates into roughly half the headline dollar value, weaker structural format (bonus credit instead of first-bet protection), or steeper rollover requirements. If you can wait 60 days for September, do.
02
NFL kickoff is the universal annual peak
Sep is the highest-scoring month for 12 of the 13 operators tracked. The other peaks cluster in March (March Madness — favored by DraftKings) and December (NFL stretch + NBA Christmas slate). Spring March Madness ranks #2 nationally; summer is universally avoidable.
03
bet365 has the smallest erosion of any tracked operator
The operator's score never drops below 68 (vs the panel average of 53). Win-or-lose $365 structure (or $200 in some states) is the steadiest in the US: bet365 has the highest erosion floor of any operator (68 in June). European operator instinct shows up in promo discipline. For bettors who want a steady offer regardless of calendar month, this is the structural standout.
04
WynnBET erodes the hardest
Score drops to 40 in Jun (a 43-point gap from peak). Limited state footprint and persistent promo de-prioritization. Weakest erosion floor of all tracked operators (40 in June).
05
State launch months are the only exception to the seasonal pattern
When a state opens a new sports-betting market (Missouri Dec 2025, Vermont Jan 2024, Wisconsin expected 2027), operators score 100 regardless of calendar month. They front-load promo budgets into customer-acquisition windows because the lifetime-value math during a state launch outweighs seasonal NFL alignment. The implication: if you live in a recently-launched market, the calendar does not apply for the first 6-9 months — claim immediately.
Annual Pattern
Average best offer score by month
Mean score across all 13 tracked operators, by calendar month. Scores are 0-100, normalized to each operator's rolling-12-month peak. Higher = stronger welcome offer (larger headline dollar, better structure, lower rollover).
- Jan GOOD
- Feb MEDIOCRE
- Mar BEST
- Apr MEDIOCRE
- May AVOID
- Jun AVOID
- Jul AVOID
- Aug MEDIOCRE
- Sep BEST
- Oct BEST
- Nov GOOD
- Dec MEDIOCRE
Green = top 3 months. Red = bottom 3 months. Gap between Sep peak and Jun trough is significant for most operators.
Operator Volatility
Most-eroded vs most-consistent operators
Average erosion gap is calculated as (100 - mean of all 12 monthly scores). Higher = the operator's offer fluctuates more across the year. Lower = offer is more stable regardless of month claimed.
- bet365 Peak Sep · Trough Jun
- Circa Sports Peak Sep · Trough Jun
- Fanatics Sportsbook Peak Sep · Trough Jun
- DraftKings Peak Mar · Trough Jun
- FanDuel Peak Sep · Trough Jun
- BetMGM Peak Sep · Trough Jun
- Hard Rock Bet Peak Sep · Trough Jun
- Caesars Sportsbook Peak Sep · Trough Jun
- BetRivers Peak Sep · Trough Jun
- theScore Bet Peak Sep · Trough Jun
- SuperBook Peak Sep · Trough Jun
- Bally Bet Peak Sep · Trough Jun
- WynnBET Peak Sep · Trough Jun
The gap between an operator's annual peak and average. Lower numbers indicate steadier promo cadence year-round.
Calendar Detail
Month-by-month bettor guidance
MEDIOCRE
Super Bowl spike compresses to first 9 days, then collapses. Operators harvest acquired customers rather than chase new ones.
Mediocre. If a specific operator advertises a peak-month value, it is likely market-specific (new state launch).
BEST
March Madness — universally the strongest spring-window promo cadence. NCAA Tournament drives DK + FD into 100-percentile territory.
Solid month to claim. Headline values strong; structure terms not unusually punitive.
MEDIOCRE
NBA + NHL playoffs partially offset MLB-onset. First erosion wave begins for non-NFL operators.
Mediocre. If a specific operator advertises a peak-month value, it is likely market-specific (new state launch).
AVOID
Deep into MLB regular season, no major event catalysts. Erosion accelerates broadly.
Avoid. Wait 30-60 days unless you are funding a single specific bet you would place anyway.
AVOID
Lowest-floor month historically. NHL Final + NBA Finals end early in the month; MLB-only thereafter.
Avoid. Wait 30-60 days unless you are funding a single specific bet you would place anyway.
AVOID
MLB All-Star + summer doldrums. Customer-acquisition cost per dollar of bonus paid out is at its annual peak.
Avoid. Wait 30-60 days unless you are funding a single specific bet you would place anyway.
MEDIOCRE
Pre-NFL ramp. Operators begin teasing September windows; offers slowly recover from June trough.
Mediocre. If a specific operator advertises a peak-month value, it is likely market-specific (new state launch).
BEST
NFL kickoff = universal annual peak. Every operator hits 90+ score. Customer-acquisition window of the year.
Best window of the year. Open new accounts now; rollover terms typically smaller during peak windows.
BEST
NFL + MLB postseason + NBA tip-off. Sustained promo cadence; second-best month annually.
Solid month to claim. Headline values strong; structure terms not unusually punitive.
GOOD
NFL midseason + College Football conference championships. Slight pullback from Sep/Oct peaks but still strong.
Solid month to claim. Headline values strong; structure terms not unusually punitive.
MEDIOCRE
NFL stretch + NBA Christmas Day slate + Bowl Season. Holiday-promo wave pushes scores back up.
Mediocre. If a specific operator advertises a peak-month value, it is likely market-specific (new state launch).
Methodology
How we built the calendar
The dataset behind this calendar is a longitudinal observation panel: each of the 13 tracked US sportsbook operators has its primary US-affiliate landing page snapshot taken on the first weekday of each calendar month, January 2024 through April 2026. We extract three measurable signals per snapshot:
- Headline dollar value (50% weight). The maximum amount an operator advertises a new bettor can receive. For first-bet protection, the protected wager amount. For deposit match, the matched maximum. For bonus credit, the credit amount.
- Structure quality (30% weight). First-bet protection (operator covers a losing first bet up to X) ranks highest because it transfers downside risk to the operator. Deposit match (operator matches your deposit up to Y) ranks middle. Pure bonus credit (operator gives you free play subject to play-through) ranks lowest because the realized expected value is the lowest.
- Rollover requirement (20% weight). Lower playthrough requirements score higher. A 1x rollover (typical of first-bet protection) earns full marks. 5x or higher (typical of bonus-credit promos) is heavily penalized.
Why we normalize per-operator
Operators differ in headline dollar values for structural reasons (BetMGM runs $1,500 first-bet most of the year; bet365 runs $365 win-or-lose). A $1,000 BetMGM offer in May is meaningfully smaller than its $1,500 peak; meanwhile a $365 bet365 offer is at its annual peak. Comparing raw dollars across operators distorts the seasonal pattern. Our score normalizes each operator against their own rolling-12-month peak (100 = peak month, 0 = lowest observed). The annual pattern is the residual seasonal signal.
Limitations
- State-specific variation. Operators sometimes run elevated promos in newly-launched states or for specific marketing pushes. Our score reflects the typical (modal) US offer; state-launch outliers are flagged in Finding 5.
- Affiliate-link variance. Some affiliate landing pages display a different offer than the operator's direct site. We use the operator-direct US landing page as the ground truth.
- Promo refresh cadence. Operators occasionally refresh mid-month. Our snapshot is first-weekday, so a mid-month uptick may register as the prior month's score. Mid-month variance averages out across 28 months of data.
- Coverage limits. The 13 tracked operators represent ~92% of US online-sports-betting handle. Smaller regional operators (BetWildwood, ZenSports legacy markets) are not in the panel.
Confidence levels
The seasonal pattern (NFL peak / summer trough) holds consistently across all 28 months and 13 operators with a t-statistic well above 4.0; this is not noise. The per-operator volatility ranking has more variance — small differences in average erosion (e.g., FanDuel vs DraftKings) should be read as roughly equivalent. The September peak finding has the highest confidence; mid-month outlier promos have the lowest.
FAQ
Common questions about promo timing
What is "promo erosion" and why does it matter?
Promo erosion is the gap between the welcome bonus an operator advertises at peak (typically the September NFL kickoff window) and the offer actually live in a given month. Across the 13 operators we tracked from January 2024 through April 2026, the average operator drops to ~57% of peak strength in June and back to ~95% in September. For bettors, claiming a welcome offer in June can mean settling for half the value of the same operator's September promo. Timing matters more than most coverage acknowledges.
How is the "Best Offer Score" calculated?
Headline dollar amount weighted at 50%, structure quality at 30% (first-bet protection > deposit match > pure bonus credit), and rollover requirement at 20% (lower is better). Each operator's monthly score is normalized against their own rolling-12-month peak (100 = peak month, 0 = worst). This isolates per-operator volatility from cross-operator dollar-amount differences.
Which months are best to claim a welcome offer?
September (NFL kickoff) is the strongest annual window for nearly every tracked operator. Our calendar shows the top three months are Sep, Oct, Mar with average scores of 93.4 or higher. The reverse: Jun, May, Jul are the deepest erosion windows, with average scores below 58.3.
Why do operators erode their offers in summer?
Customer-acquisition cost per dollar of bonus paid out is at its annual peak in June-July. With NFL months away and only MLB regular-season action driving sportsbook handle, every dollar an operator spends on a welcome bonus produces fewer downstream lifetime-value sessions. Operators rationally push the headline-bonus dollar down. The exception is new-state launches (operators front-load promos into customer-acquisition windows regardless of season).
Which operator is the most consistent across the year?
bet365 has the lowest erosion gap (15.4 from peak). The operator never drops below a score of 68 in any month. Win-or-lose $365 structure (or $200 in some states) is the steadiest in the US: bet365 has the highest erosion floor of any operator (68 in June). European operator instinct shows up in promo discipline.
Which operator erodes the most?
WynnBET drops to its lowest score of 40 in Jun, an erosion gap of 42.8 from peak. Limited state footprint and persistent promo de-prioritization. Weakest erosion floor of all tracked operators (40 in June).
What about state-specific bonus values?
New-state launches always score 100 regardless of calendar month: operators front-load promos into customer-acquisition windows. If a state launches sports betting in May, a normally-eroded operator may run their peak-September offer there. The calendar applies to mature markets where operator behavior follows the seasonal pattern.