Executive Summary

When market-leading books move their lines, the rest of the market eventually follows. But not immediately. The gap between a leading book's move and follower adoption creates a window of opportunity for alert bettors. This study measures those reaction times across 24 major sportsbooks and six sports to identify where the best windows exist.

The findings confirm what experienced bettors suspect: there is significant variation in reaction speed between books, between sports, and between bet types. Exploiting these differences — often called "line shopping on steroids" — is a viable source of edge for bettors with speed, accounts at multiple books, and the discipline to act quickly.

Methodology

We monitored line movements at 24 sportsbooks using automated scraping tools, sampling each book every 15 seconds during active market hours. A "reaction" was defined as a line adjustment at a follower book that matched or exceeded a move at a leading book (Pinnacle, CRIS, or Circa) within the preceding 60 minutes.

Reaction time was measured as the difference between the timestamp of the leader's move and the timestamp of the follower's matching adjustment. Only moves of 0.5 points or greater on spreads, or 5+ cents on moneylines, were included.

Data was collected from September through November 2024, capturing peak betting season across NFL, college football, NBA, and college basketball.

Overall Reaction Times

The fastest-reacting books are, unsurprisingly, other market-makers. Pinnacle leads, so it has no "reaction time" in the traditional sense. Circa Sports responds to Pinnacle moves in an average of 1.2 minutes. CRIS takes 1.8 minutes.

U.S. recreational books are slower. DraftKings averages 2.8 minutes. FanDuel takes 3.1. BetMGM and Caesars are slower still at 4.5 and 5.2 minutes respectively.

The slowest books — primarily smaller offshore operators — take an average of 14.7 minutes to react. One book in our sample took over 40 minutes to adjust a college basketball total after a Pinnacle move.

These averages conceal significant variation. A major NFL line move might see DraftKings react in 45 seconds. A mid-major college basketball move might take them 8 minutes. The importance of the game and the amount of money already on the book matters enormously.

Sport-Specific Patterns

Books react fastest to NFL line moves (average 1.9 minutes across all followers) and slowest to college basketball (5.8 minutes). This pattern holds across virtually every book in our sample.

The reasons are straightforward. NFL attracts the most betting volume and the most automated trading. Books have dedicated NFL traders and automated systems that respond immediately. College basketball is lower priority — fewer traders, less automation, and less overall attention.

This creates an interesting dynamic for bettors. The sport where line shopping is most discussed (NFL) is actually where the windows are smallest. The sports where windows are largest (college basketball, mid-major soccer) are where fewer bettors are looking.

"Everyone shops NFL lines. Almost no one shops Southland Conference basketball totals. The latter is where the real edges live."

Time-of-Day Effects

Reaction times vary significantly based on when the move occurs. Moves during peak U.S. betting hours (12pm-8pm ET on weekends) see faster reactions than moves overnight or during weekdays.

Average reaction times by period:

  • Weekend afternoons (12pm-8pm ET): 2.4 minutes
  • Weekday evenings (5pm-11pm ET): 3.1 minutes
  • Overnight U.S. (12am-8am ET): 6.8 minutes
  • Early morning (8am-12pm ET): 4.2 minutes

Overnight moves — often driven by Asian market activity or European soccer lines — produce the largest windows for U.S. bettors willing to wake up early or stay up late.

Exploiting the Windows

We tested a practical strategy: monitor Pinnacle for moves, then immediately bet the old line at the slowest-reacting books where you have accounts. The results were positive but highly dependent on execution speed and account status.

Bettors who could place bets within 3 minutes of detecting a move at their slowest book achieved +4.2% ROI over 847 opportunities. However, this assumes:

  • Funded accounts at multiple slow-reacting books
  • Immediate line availability (not always the case — books sometimes pull lines during moves)
  • No account limits restricting bet size
  • Accurate move detection within 30 seconds of origin

In practice, achieving all four conditions simultaneously is difficult. The theoretical edge is real; capturing it consistently requires infrastructure and organization that most bettors lack.

Which Books to Target

Based on reaction time data, the best targets for line-shopping exploitation are:

Tier 1 targets (slowest to react): Smaller offshore books with 10+ minute average reactions. Harder to fund, less reliable, but enormous windows.

Tier 2 targets: Caesars and BetMGM, averaging 4-5 minutes. Reliable, well-funded, but increasingly automated. The window exists but is narrowing.

Tier 3 targets: DraftKings and FanDuel at 2.5-3 minutes. Only viable if you're extremely fast and the move is significant.

The Future of Reaction Time

Every year, books get faster. Automated line management systems are now standard at major U.S. books. The 3-minute window that existed in 2022 is a 90-second window in 2024. By 2026, major books may respond to market moves in under 60 seconds.

For bettors, this means the line-shopping edge is a diminishing resource. It will not disappear entirely — smaller books will always be slower — but the easy money is already gone. The bettor relying on slow book reactions needs either exceptional speed, access to obscure books, or a pivot toward predictive modeling as their primary edge source.