The single most important concept in +EV betting might be one most bettors have never heard of: sharp books. Understanding which sportsbooks set the most accurate lines — and which ones don’t — is the foundation of finding real value.
What Makes a Book “Sharp”?
A sharp sportsbook is one that:
Welcomes professional bettors instead of limiting or banning them
Sets low-hold lines (low vig) to attract volume from sharp players
Moves lines in response to sharp action rather than public money
Has the most accurate closing lines in the market
The most well-known sharp book is Pinnacle. They don’t offer promos, they don’t have a flashy app, and they’re not available in most US states. But their closing lines are consistently the most accurate predictor of actual game outcomes in all of sports betting.
Other sharp-leaning books include Circa (low-hold NFL and NBA lines) and various international books that cater to professional bettors.
Soft Books
On the other end, soft books (also called “retail” or “recreational” books) cater to casual bettors:
DraftKings, FanDuel, BetMGM, Caesars — the big US-facing books
They offer promos, odds boosts, and user-friendly interfaces
They charge higher vig (more juice built into lines)
They limit or ban bettors who win too much
Their lines are less accurate, especially on player props and smaller markets
This isn’t a knock on soft books. They’re designed for the mass market and they’re great at it. But from a +EV perspective, the gap between their lines and sharp lines is where the money is.
Using Sharp Lines as Your Benchmark
Here’s the framework that drives profitable betting:
Take the sharpest available lines on a market
Strip out the vig to get the no-vig fair probability
Compare that fair value against every other sportsbook
If a book offers better odds than fair value, that’s +EV
Worked Example
Let’s say the sharp market on an NBA total looks like this:
Sharp line: O/U 215.5 — Over -105 / Under -105 (2.1% total vig)
Strip the vig:
Over implied: 51.2% → no-vig: 50%
Under implied: 51.2% → no-vig: 50%
Now check a soft book:
DraftKings: Over 215.5 at -102
Implied probability: 50.5%
Fair value: 50%
This is roughly break-even, not +EV
Check another:
BetMGM: Over 214.5 at -110
The line is a full point lower (214.5 vs 215.5) at standard juice
Getting the over at a lower number than the sharp market says it should be — that’s +EV
The sharp line is your truth. Everything else is measured against it.
Why Sharp Books Are More Accurate
They Let Sharps Bet
When a professional bettor finds a mispriced line, they bet into it. The book moves the line. Over time, this constant pressure from informed bettors pushes lines toward the true probability. Pinnacle essentially crowdsources accuracy from the smartest bettors in the world.
Soft books limit sharps before they can move the line. The result: less market correction, less accurate prices.
They Charge Less Vig
A Pinnacle NFL spread might be -103/-103. A DraftKings spread is -110/-110. The lower vig means Pinnacle’s implied probabilities are already closer to true probabilities before you even strip the vig.
Closing Line Value
Here’s the key metric: closing line value (CLV). If you consistently bet at prices that are better than the closing line (the final line before the game starts), you are almost certainly a winning bettor.
Sharp books’ closing lines are the gold standard. Their closing line is the market’s best estimate of the true probability of an outcome. Beating that number is the definition of having an edge.
Putting It Into Practice
The sharp-book-based fair value approach works like this:
Pull odds from sharp markets and all major US sportsbooks
Calculate no-vig fair odds from the sharpest available lines
Compare every other book’s odds against that fair benchmark
When a book offers odds that exceed fair value — that’s the +EV play
The sharp line tells you the true probability. The soft books occasionally offer prices that don’t reflect that truth. Finding those gaps is the entire game.
Common Questions
“Can I just bet at Pinnacle?”
If you have access, sure — but Pinnacle’s vig is so low that there’s almost no edge to be found at Pinnacle. The value of sharp books isn’t betting at them. It’s using their lines as a benchmark to find mispricing at books you can bet at.
“Do soft books always have worse lines?”
Not on every single bet. Soft books occasionally have the best line on a market, especially right after they open a line or after heavy one-sided action pushes the line too far. The point isn’t that soft books are always wrong — it’s that they’re wrong more often than sharp books, and that’s where the edge comes from.
“Why don’t soft books just copy sharp lines?”
They do, to some extent. Most books start with similar opening lines. But their books are balanced differently (more recreational action), they respond to different signals (public money vs. sharp money), and they charge more vig. These factors create persistent gaps.
“How much of an edge are we talking about?”
On main markets (spreads, totals), the edge is typically small — 1-3%. On player props, the edge is often 5-10%+ because soft books price props with less precision. That’s why props are where most of the +EV lives.
Key Takeaways
Sharp books (like Pinnacle) have the most accurate lines because they welcome professional bettors
Soft books (DraftKings, FanDuel, etc.) charge more vig and have less accurate lines
The gap between sharp fair value and soft book odds is where +EV opportunities live
Strip the vig from sharp lines to get the true probability, then compare against all books
You don’t need to bet at sharp books — you need to use their lines as your benchmark
+EV tools automate this process: sharp fair value calculation → comparison across books → edge identification
