Question: intended timezone convention for options-chain DTE

[snigdhachoppac]

**Describe the behavior

Options-chain DTE calculations appear to depend on the local timezone of the machine running OpenBB.

For example, the YFinance options-chain provider obtains the exchange timezone:

tz = timezone(underlying.get("exchangeTimezoneName", "UTC"))

However, DTE is calculated using the machine’s local calendar date:

now = datetime.now().date()
dte = (exp - now).days

I found similar local-date calculations in other options-chain providers, so I wanted to confirm the intended cross-provider convention before proposing a code change.

** To reproduce

At the same instant worldwide:

from datetime import datetime, timezone
from pytz import timezone as get_timezone

instant = datetime(
    2026,
    7,
    28,
    1,
    30,
    tzinfo=timezone.utc,
)

exchange_timezone = get_timezone("America/New_York")
machine_timezone = get_timezone("Asia/Tokyo")

exchange_date = instant.astimezone(exchange_timezone).date()
machine_date = instant.astimezone(machine_timezone).date()

expiration = datetime(2026, 7, 31).date()

exchange_dte = (expiration - exchange_date).days
machine_dte = (expiration - machine_date).days

print("Exchange calendar date:", exchange_date)
print("Machine calendar date:", machine_date)
print("DTE using exchange date:", exchange_dte)
print("DTE using machine date:", machine_dte)

Output:

Exchange calendar date: 2026-07-27
Machine calendar date: 2026-07-28
DTE using exchange date: 4
DTE using machine date: 3

The same contract can therefore receive a different DTE depending on the user’s machine timezone.

** Expected behavior / question

What is the intended convention for options-chain DTE across providers?

1. Machine-local date
2. UTC date
3. Exchange-local date
4. A date or DTE supplied directly by the provider

I would be happy to contribute a deterministic regression test and implementation once the intended behavior and scope are confirmed.

** Desktop

• OS: macOS
• Python version: 3.14.4
• Branch: develop

** Additional context

I have not changed the implementation yet because multiple providers appear to use the machine-local date, and changing only YFinance could introduce inconsistent behavior across providers.

[deeleeramone]

Hi, you're right. For someone overseas this would cause drift depending on what time of day it was according to their local machine. It should always be localized to the exchange. Forthcoming V5 provider extensions will enforce this, so don't worry about proposing any changes. Thanks.