2,430 Games a Season — Your Bankroll Needs a Plan
My worst month betting on baseball was June 2021. I had a winning record — 58% on moneylines — and still lost money. The reason was embarrassingly simple: I had no staking plan. I was putting three units on games I felt strongly about and one unit on everything else, but “felt strongly” turned out to be code for “the public favourite I had already read three articles about.” By month’s end, my big bets had a losing record and my small bets had a winning one. The bankroll did not care about my win percentage; it cared about the distribution of my stakes.
MLB presents a unique bankroll challenge because the volume of betting opportunities is enormous. Each team plays 162 regular season games, producing 2,430 total games across the league — more than any other major American sport. If you bet even a fraction of those, the cumulative effect of your staking method dwarfs the effect of any individual pick. A disciplined bettor with average selections will outperform a sharp bettor with chaotic sizing over a full season. I have seen it happen in my own results and in the results of every betting circle I have been part of.
Flat Betting, Percentage Method and Simplified Kelly Compared
There are three mainstream approaches to stake sizing, and after nine years of testing each one across multiple seasons, I can tell you that the differences between them are smaller than the betting public believes — but real enough to matter over thousands of wagers.
Flat betting is the simplest: you risk the same amount on every bet regardless of your confidence level. If your unit is £20, every wager is £20. The advantage is behavioural — it removes the temptation to oversize on “locks” that are never actually locked. The disadvantage is mathematical: if you genuinely identify bets with varying edge sizes, flat betting underexploits the best ones and overexposes on the weakest. For most bettors, though, the behavioural advantage outweighs the mathematical cost. MLB moneyline favourites win 58-62% of games historically, and at those hit rates, simply surviving the variance is more important than optimising the edge.
Percentage betting adjusts your unit size to a fixed percentage of your current bankroll — typically 1-3%. A £1,000 bankroll at 2% means your first bet is £20; if you win and your bankroll grows to £1,040, your next bet is £20.80. The system automatically scales up during winning streaks and scales down during losing runs, which provides built-in protection against ruin. The downside is that it requires recalculating after every bet, which sounds trivial but becomes genuinely tedious when you are placing four or five wagers on a Saturday afternoon slate.
The Kelly Criterion is the mathematically optimal staking method for maximising long-term bankroll growth, and it is also the one that gets the most people into trouble. Full Kelly tells you to bet a fraction of your bankroll equal to your edge divided by the odds. The problem is that it requires you to accurately estimate your edge on every bet, which no one can do consistently. A 5% overestimate of your edge can lead to catastrophic oversizing. I use a simplified version — half Kelly, sometimes quarter Kelly — which sacrifices some theoretical growth for a massive reduction in volatility. Even half Kelly assumes you know your edge to within a few percentage points, so I treat it as a ceiling rather than a target.
Adjusting Unit Size for Multi-Game Series Exposure
Everything above applies to single-game betting. Series betting introduces an additional layer: correlated exposure. If you bet on the Dodgers to win Game 1, Game 2, and the series outright, you do not have three independent bets — you have three overlapping positions that all lose together if the Dodgers collapse. Your effective exposure is much higher than your nominal stake.
I handle this with a simple rule: total exposure to any single series cannot exceed a fixed percentage of my bankroll, regardless of how many individual bets I place within it. For me, that ceiling is 5% during the regular season and 8% during the postseason, where the edge opportunities tend to be larger and the markets more liquid. If I have already risked 4% of my bankroll on a series and a new opportunity appears in Game 3, I either skip it or reduce an existing position.
The other adjustment for series betting is temporal. In a seven-game World Series, you might have open positions for a week. Your bankroll is partially locked up in those positions, which reduces the capital available for other bets. I account for this by setting aside a “series fund” at the start of the postseason — a designated portion of my bankroll that is exclusively for series wagers — and keeping the rest available for standalone game bets. This prevents the common mistake of being fully invested in a series position with no dry powder left when a juicy Game 5 line appears.
When to Stop: Setting Loss Limits and Taking Breaks
The US sports betting industry generated a record $16.96 billion in revenue in 2025 — a 22.8% increase year on year — on total handle of $166.94 billion. Those numbers represent money that moved from bettors to operators, and they grew because more people bet more often without adequate controls. Bill Miller of the American Gaming Association framed it positively, noting another strong year for the industry. From a bettor’s perspective, those same numbers are a reminder that the house’s record year is made up of millions of individual losing accounts.
I set three hard limits at the start of every season. First, a daily loss limit: if I lose more than 3% of my bankroll in a single day, I stop betting until tomorrow. Second, a weekly loss limit: 7% of my bankroll triggers a two-day break from all wagering. Third, a monthly review: if my bankroll has declined by more than 15% from its monthly opening balance, I stop betting for the remainder of the month and spend the time reviewing my process rather than chasing losses.
These limits are not negotiable, and I enforce them mechanically rather than emotionally. The temptation to chase after a bad day is strongest precisely when your judgment is worst. The underdog ROI data and every other edge I discuss on this site only works if you are still solvent when the edge materialises. Bankroll management is not the exciting part of MLB betting, but it is the part that determines whether everything else matters.
