Spread in Basis Points

One basis point is $0.01\%$, i.e. $1/10,000$.

Divide the spread by the midpoint $100.25$.

1. 1. Spread and midpoint

   The spread is $0.50$ and the midpoint is $100.25$.

2. 2. Convert

   Scale the ratio by $10,000$.

   $$\frac{0.50}{100.25}\times 10,000\approx 49.88\text{ bp}$$

3. 3. Key idea

   Quote spreads relative to the midpoint, not the bid, unless told otherwise.

Answer: 49.88