30E+/360: Definition & Meaning | Bondfish
30E+/360 is a day-count convention that, like 30E/360, treats months as 30 days and the year as 360 days — but when the end date of a period falls on the 31st, it rolls forward to the 1st of the following month instead of back to the 30th.
What it means
Day-count conventions are the market’s rules for measuring time between two dates when computing bond interest. In the 30/360 family, each month is standardized to 30 days. The variants differ only in how they handle dates that fall on the 31st.
Under 30E+/360, a start date on the 31st is moved back to the 30th, exactly as under 30E/360. The difference is the end date: instead of trimming the 31st back to the 30th, 30E+/360 pushes it forward to the 1st of the next month. That adds one extra day to the count whenever a period ends on the 31st. The convention is a rarer variant, seen in some Eurobond and derivatives documentation.
Why it matters for bond investors
The extra day sounds trivial, but accrued interest is computed to the exact day, so the convention written into a bond’s terms changes the amount a buyer pays on settlement. When you compare quotes or check a broker’s accrued-interest figure, make sure you know which 30/360 variant the bond’s documentation specifies.
Example
From 15 March to 31 May:
30E/360 → end date becomes 30 May → 30×2 + (30−15) = 75 days.
30E+/360 → end date becomes 1 June → 30×3 + (1−15) = 76 days.
Related terms
This definition is for general information only and is not investment advice. Bond investing involves risk, including possible loss of principal.