Why Does the Same Options Strategy Make Money in Backtests but Fall Short Live?
The directional idea can be right while the execution assumptions are wrong. Match contracts, quotes, fills, and fees to see where the backtest-to-live gap comes from.
Trading Costs
Understand how trading fees, slippage and perpetual funding affect the profit left after costs.
同一期权策略，回测很赚钱，实盘为什么总少一大截？
方向没变，成交价变了，期权利润也可能缩水。把同一合约的回测价格、报价和成交记录对齐，先查清差额来自哪里。
每笔只赚一点点，网络慢半秒会不会把利润全部吃掉？
网络慢半秒，亏的是时间还是成交价？用一笔 3 元薄利的例子，把等待、差价与费用分开，再沿真实运行记录查原因。
Can Half a Second of Latency Wipe Out a Thin Trading Edge?
A thin profit leaves little room for worse fills. Separate the delay from its cost, then trace one order before paying for a faster setup.
Why Does My Backtest Barely Make Money After Trading Costs?
A trade earns 12 basis points before costs. Fees, the spread, and slippage leave just 1. Here’s how to check what your backtest actually includes.
回测明明赚钱，为什么把所有交易成本算进去，利润就快没了？
每笔毛赚 12 个基点，扣完手续费、点差和滑点只剩 1 个。先把这笔账算清，再检查成本有没有漏算或重复扣除。
Your Backtest Made 20%. What Is Left After Real Slippage?
In this worked example, a 20% backtest return falls to 10% with 0.05% adverse slippage per side—and reaches zero at 0.10%.