Add the published 2027 CME holiday dates and hours

[AlexCatarino]

Fill in the 2027 holiday calendar for the CME, CBOT, NYMEX and COMEX entries, from CME's published schedule.

Description

The CME-family calendars carried nothing for 2027 beyond New Year's Day and the observed Juneteenth, so every session and every expiry computed into 2027 counted the rest of the year as ordinary business days.

Dates, on the four market-wide entries. Each appears in OPM's published 2027 federal holiday schedule, and CME's own 2027 holiday notes state the trade dates around it.

Full closes, where CME states there is no trade date at all:

Date	Holiday
1/1/2027	New Year's Day
3/26/2027	Good Friday - "No trading for Friday March 26th trade date"
12/24/2027	Christmas, observed Friday; last trade date is Thursday the 23rd

Bank holidays, where CME trades but the banks are closed, so only expiry dates move: 1/18, 2/15, 5/31, 6/18, 7/5, 9/6, 10/11, 11/11, 11/25 and 12/31/2027.

Per-product hours, from CME's own published 2027 schedule. The trading-hours page is backed by

/services/trading-hours-by-product?fromEventDate=&toEventDate=

which serves per-product events for 2026 and 2027, and only those two years - exactly CME's publication window. Each product's published 2027 event signature is matched against that same product's 2026 holidays, whose treatment this database already records from CME's published 2026 calendar. Where the signature matches, the recorded treatment is what CME publishes for 2027 as well. A date with no events at all is unambiguous on its own: the product does not trade.

Notes

• Nothing is projected from a neighbouring year, and no date on or before today is touched. The change is additive: 12 distinct dates, all between 1/18/2027 and 12/31/2027, with no removals and no existing value altered.
• The extraction is included only for the 164 of 177 products whose 2026 data it reproduces exactly under leave-one-out. The other 13 keep the market-wide dates alone. They are mostly crypto and index products whose published schedules are placeholders (16:01 pre-open, 16:02 open), plus HE, LE, GF and LBR, where this database and CME disagree about the day after Thanksgiving and Christmas Eve 2026 and it is not clear which is right.
• This corrects values a projection from 2026 would have got wrong. Crude oil closes at 14:30 on Independence Day 2027, not the 13:00 it uses in 2026, because the holiday is observed on a Monday rather than a Friday; and the E-mini S&P has no early close on Christmas Eve 2027 though it had one in 2026.
• The eight remaining 2026 holidays were checked against the same source: 883 of 883 recorded values for those products agree, so nothing before 2027 needs changing.
• 2028 and later are not included. The endpoint returns nothing for them, so they could only be projected.

Related Issue

n/a

Motivation and Context

Keeps trading sessions and futures expiry dates correct through 2027 for the CME family.

Requires Documentation Change

N/A. The QuantConnect/Documentation repo regenerates MHDB-related docs on a weekly schedule.

How Has This Been Tested?

FuturesExpiryFunctionsTests, MarketHoursDatabaseTests, SecurityExchangeHoursTests, SymbolPropertiesDatabaseTests, SymbolRepresentationTests - 531/531 pass.

Six recorded expiries move, all 2027 contracts. Each matches a 2021 contract in exactly the same weekday configuration that is already recorded that way:

Contract	Was	Now	Precedent already in the file
BK, CSX May 2027	2027-05-31	2027-05-28	2021-05-28, Memorial Day on the 31st
BK, CSX Dec 2027	2027-12-31	2027-12-30	2021-12-30, New Year observed Friday
HH Jun 2027	2027-05-27	2027-05-26	2021-05-26
HH Jan 2028	2027-12-29	2027-12-28	2021-12-28

Both expiry rules were replayed independently over every recorded row for those three roots: 106 of 108, 103 of 105 and 149 of 151 reproduce the recorded value exactly, and the only differences are the six above.

Types of changes

• Bug fix / data update (non-breaking)

Checklist:

• My code follows the code style of this project.
• I have read the CONTRIBUTING document.
• All new and existing tests passed.