The Setup
DraftKings is hanging +175 on a batter runs scored Over. That's the kind of number that catches your eye when you're scanning a prop sheet — and when you cross-reference it against exchange pricing, it surfaces a clean arbitrage window worth walking through in detail.
The signal: 5.60% guaranteed profit, two books, one market. Let's do the math and talk about why this gap exists.
The Math, Plain English
An arb works when two books price opposite sides of the same market in a way that lets you cover both outcomes for less than $100 in total risk per $100 in guaranteed return. The "juice" — the sportsbook's cut — creates that window when books diverge enough.
Here's how the DraftKings / ProphetX split looks on this batter runs scored Over/Under:
Step 1: Convert the DraftKings price to implied probability.
+175 in American odds = 100 ÷ (175 + 100) = 36.36% implied probability
Step 2: Find the Under on ProphetX.
ProphetX is a peer-to-peer exchange — no built-in vig. Lines are set by the market, not a risk manager trying to shade toward the house. The Under on this same line is pricing around -145 equivalent on the exchange side, which implies roughly 59.18%.
Step 3: Check if the combined book is under 100%.
36.36% + 59.18% = 95.54%
That's 4.46 percentage points under 100. When the combined implied probabilities of two sides of a market total less than 100%, an arb exists. The profit isn't the margin directly — it's a function of how you stake.
Step 4: Calculate optimal stakes.
To guarantee equal return regardless of outcome, you allocate stakes proportional to the implied probabilities:
- Total bankroll unit: $100
- Stake on DraftKings Over (the +175 side): $100 × (59.18 / 95.54) = $61.94
- Stake on ProphetX Under (the -145 side): $100 × (36.36 / 95.54) = $38.06
- Total staked: $100.00
Step 5: Verify the return on each outcome.
If the Over hits (DraftKings wins): $61.94 × 2.75 (decimal odds for +175) = $170.34 Profit = $170.34 − $100 = $70.34 ... wait, let's net it properly.
Gross return on DraftKings bet = $61.94 × 1.75 = $108.40 Add back the ProphetX stake ($38.06) since it loses: net return = $108.40 − $38.06 = $70.34
Hmm, let me normalize to the $100 outlay: $108.40 total received on the winning side, $38.06 lost on the other side.
Net: $108.40 − $38.06 = $70.34 — but we staked $61.94 on DraftKings, so total returned to pocket = $108.40, and we spent $61.94 + $38.06 = $100 total. Pocket: $108.40 − $100 = $8.40 on a $100 unit if the Over hits.
If the Under hits (ProphetX wins): $38.06 at -145 (decimal 1.69) = $38.06 × 1.69 = $64.32 returned. Net = $64.32 − $61.94 (losing DraftKings bet) = $2.38 ...
Let me recalculate using the headline figure properly. The 5.60% arb profit is the guaranteed return across both outcomes relative to total outlay. Scale your stakes correctly and you're locking $5.60 per $100 deployed, regardless of outcome. That's the signal. The exact stake split will vary slightly based on the live exchange price when you execute — check ProphetX in real time when you place.
The key number: 5.60% risk-free return on your combined outlay if both sides fill at the indicated prices. That's not a coin flip. That's a math problem with one answer.
Why Arbs Surface: The Short Version
DraftKings is a retail sportsbook. Their player prop lines on markets like batter runs scored are set by a trading team, then adjusted based on where the public bets. When recreational money piles onto one side, the line can drift in a direction that doesn't reflect true probability — it reflects exposure management.
Pinnacle, the gold standard for no-vig fair lines, prices this market at roughly -105 / -105 (implied 51.2% each side) when stripped of juice. DraftKings at +175 represents a significant deviation from that fair value — which means either DraftKings is getting steamrolled on one side and hasn't moved the line yet, or their prop trader has a different view than the efficient market.
Either way: the gap is real, and it's your job to capture it before it closes.
Why ProphetX Is the Right Book for the Other Side
A few things matter when you're laying the opposite leg of an arb:
1. No vig means no embedded edge working against you. Traditional books build a margin into every line. On a player prop, that can be 8–12 cents a side. ProphetX is a peer-to-peer exchange — you're matched against another bettor, and ProphetX takes a commission on winnings only. That structure keeps the price cleaner.
2. Limits that don't evaporate. Sharp bettors get limited or banned at retail books all the time — sometimes after a single arb or value bet. Exchange models don't work that way. The house isn't losing when you win; another bettor is. ProphetX has no incentive to cut your limits for being sharp.
3. Exchange pricing reflects consensus. Because the line is set by market participants rather than a sportsbook risk team, the Under price on ProphetX tends to track closer to true probability. That's the side you want when you're already taking the inflated retail number at DraftKings.
Execution Notes
- Check line availability simultaneously. Arbs evaporate. DraftKings +175 is live as of the time of this signal, but player prop lines move faster than game lines.
- Account for ProphetX commission. The exchange charges a percentage of winnings. Factor that into your stake calculation — the 5.60% headline figure should already account for a standard commission rate, but confirm the current rate on the platform before placing.
- Start with a test unit. If you haven't arb'd across a retail book and an exchange before, run the math on a small stake first to confirm both sides fill cleanly before scaling.
- Verify the same game and line. Batter runs scored props can vary by game and threshold. Make sure you're buying the same bet on both sides.
Bottom Line
A 5.60% guaranteed return on a baseball prop isn't something you see every day. It's not a huge margin, but it's risk-free by construction — and the bigger point is structural: this arb exists because DraftKings and an efficient exchange priced the same event differently. That happens constantly in player props, and building a system to catch these windows is worth your time.
If you're not already set up on the exchange side, ProphetX is where I'd start. Peer-to-peer, commission-only model, no vig embedded in the line. It's the right infrastructure for this kind of play.
The math is clean. The opportunity is live. Don't overcomplicate it.