diff --git a/docs/conf.py b/docs/conf.py
index 4f14967..2815f02 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -9,7 +9,7 @@
 project = 'tastytrade'
 copyright = '2023, Graeme Holliday'
 author = 'Graeme Holliday'
-release = '6.5'
+release = '6.6'
 
 # -- General configuration ---------------------------------------------------
 # https://www.sphinx-doc.org/en/master/usage/configuration.html#general-configuration
diff --git a/requirements.txt b/requirements.txt
index d9be753..ba2398e 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -4,6 +4,7 @@ flake8==5.0.4
 isort==5.11.5
 types-requests==2.31.0.1
 websockets==11.0.3
+pandas_market_calendars==4.3.3
 pydantic==1.10.11
 pytest==7.4.0
 pytest_cov==4.1.0
diff --git a/setup.py b/setup.py
index bbe7ff4..757b4d5 100644
--- a/setup.py
+++ b/setup.py
@@ -7,7 +7,7 @@
 
 setup(
     name='tastytrade',
-    version='6.5',
+    version='6.6',
     description='An unofficial SDK for Tastytrade!',
     long_description=LONG_DESCRIPTION,
     long_description_content_type='text/x-rst',
@@ -18,7 +18,8 @@
     install_requires=[
         'requests<3',
         'websockets>=11.0.3',
-        'pydantic<2'
+        'pydantic<2',
+        'pandas_market_calendars>=4.3.3'
     ],
     packages=find_packages(exclude=['ez_setup', 'tests*']),
     include_package_data=True
diff --git a/tastytrade/__init__.py b/tastytrade/__init__.py
index b731a2d..7297999 100644
--- a/tastytrade/__init__.py
+++ b/tastytrade/__init__.py
@@ -2,7 +2,7 @@
 
 API_URL = 'https://api.tastyworks.com'
 CERT_URL = 'https://api.cert.tastyworks.com'
-VERSION = '6.5'
+VERSION = '6.6'
 
 logger = logging.getLogger(__name__)
 logger.setLevel(logging.DEBUG)
diff --git a/tastytrade/account.py b/tastytrade/account.py
index 6b94f5c..ff5b04e 100644
--- a/tastytrade/account.py
+++ b/tastytrade/account.py
@@ -1002,7 +1002,7 @@ def place_order(
         self,
         session: Session,
         order: NewOrder,
-        dry_run=True
+        dry_run: bool = True
     ) -> PlacedOrderResponse:
         """
         Place the given order.
@@ -1032,7 +1032,7 @@ def place_complex_order(
         self,
         session: Session,
         order: NewComplexOrder,
-        dry_run=True
+        dry_run: bool = True
     ) -> PlacedOrderResponse:
         """
         Place the given order.
diff --git a/tastytrade/instruments.py b/tastytrade/instruments.py
index f65c6c6..1fb2fe0 100644
--- a/tastytrade/instruments.py
+++ b/tastytrade/instruments.py
@@ -496,7 +496,7 @@ def streamer_symbol_to_occ(cls, streamer_symbol) -> str:
         if match is None:
             return ''
         symbol = match.group(1)[:6].ljust(6)
-        exp = datetime.strptime(match.group(2), '%y%m%d').strftime('%Y%m%d')
+        exp = match.group(2)
         option_type = match.group(3)
         strike = match.group(4).zfill(5)
         if match.group(6) is not None:
diff --git a/tastytrade/order.py b/tastytrade/order.py
index 1c97d5f..10600ec 100644
--- a/tastytrade/order.py
+++ b/tastytrade/order.py
@@ -346,7 +346,7 @@ class PlacedOrderResponse(TastytradeJsonDataclass):
     Dataclass grouping together information about a placed order.
     """
     buying_power_effect: BuyingPowerEffect
-    fee_calculation: FeeCalculation
+    fee_calculation: Optional[FeeCalculation] = None
     order: Optional[PlacedOrder] = None
     complex_order: Optional[PlacedComplexOrder] = None
     warnings: Optional[List[Message]] = None
diff --git a/tastytrade/utils.py b/tastytrade/utils.py
index 3e39356..28deede 100644
--- a/tastytrade/utils.py
+++ b/tastytrade/utils.py
@@ -1,6 +1,129 @@
+from datetime import date, timedelta
+
+import pandas_market_calendars as mcal  # type: ignore
 from pydantic import BaseModel
 from requests import Response
 
+NYSE = mcal.get_calendar('NYSE')
+
+
+def get_third_friday(day: date = date.today()) -> date:
+    """
+    Gets the monthly expiration associated with the month of the given date,
+    or the monthly expiration associated with today's month.
+
+    :param day: the date to check, defaults to today
+
+    :return: the associated monthly
+    """
+    day = day.replace(day=1)
+    day += timedelta(weeks=2)
+    while day.weekday() != 4:  # Friday
+        day += timedelta(days=1)
+    return day
+
+
+def get_tasty_monthly() -> date:
+    """
+    Gets the monthly expiration closest to 45 days from the current date.
+
+    :return: the closest to 45 DTE monthly expiration
+    """
+    day = date.today()
+    exp1 = get_third_friday(day + timedelta(weeks=4))
+    exp2 = get_third_friday(day + timedelta(weeks=8))
+    day45 = day + timedelta(days=45)
+    return exp1 if day45 - exp2 < exp2 - day45 else exp2
+
+
+def _get_last_day_of_month(day: date) -> date:
+    if day.month == 12:
+        last = day.replace(day=1, month=1, year=day.year + 1)
+    else:
+        last = day.replace(day=1, month=day.month + 1)
+    return last - timedelta(days=1)
+
+
+def get_future_fx_monthly(day: date = date.today()) -> date:
+    """
+    Gets the monthly expiration associated with the FX futures: /6E, /6A, etc.
+    As far as I can tell, these expire on the first Friday prior to the second
+    Wednesday.
+
+    :param day: the date to check, defaults to today
+
+    :return: the associated monthly
+    """
+    day = day.replace(day=1)
+    day += timedelta(weeks=1)
+    while day.weekday() != 2:  # Wednesday
+        day += timedelta(days=1)
+    while day.weekday() != 4:  # Friday
+        day -= timedelta(days=1)
+    return day
+
+
+def get_future_treasury_monthly(day: date = date.today()) -> date:
+    """
+    Gets the monthly expiration associated with the treasury futures: /ZN,
+    /ZB, etc. According to CME, these expire the Friday before the 2nd last
+    business day of the month. If this is not a business day, they expire 1
+    business day prior.
+
+    :param day: the date to check, defaults to today
+
+    :return: the associated monthly
+    """
+    last_day = _get_last_day_of_month(day)
+    first_day = last_day.replace(day=1)
+    valid_range = [d.date() for d in NYSE.valid_days(first_day, last_day)]
+    itr = valid_range[-2] - timedelta(days=1)
+    while itr.weekday() != 4:  # Friday
+        itr -= timedelta(days=1)
+    if itr in valid_range:
+        return itr
+    return itr - timedelta(days=1)
+
+
+def get_future_metal_monthly(day: date = date.today()) -> date:
+    """
+    Gets the monthly expiration associated with the metals futures: /GC, /SI,
+    etc. According to CME, these expire on the 4th last business day of the
+    month, unless that day occurs on a Friday or the day before a holiday, in
+    which case they expire on the prior business day.
+
+    :param day: the date to check, defaults to today
+
+    :return: the associated monthly
+    """
+    last_day = _get_last_day_of_month(day)
+    first_day = last_day.replace(day=1)
+    valid_range = [d.date() for d in NYSE.valid_days(first_day, last_day)]
+    itr = valid_range[-4]
+    next_day = itr + timedelta(days=1)
+    if itr.weekday() == 4 or next_day not in valid_range:
+        return valid_range[-5]
+    return itr
+
+
+def get_future_grain_monthly(day: date = date.today()) -> date:
+    """
+    Gets the monthly expiration associated with the grain futures: /ZC, /ZW,
+    etc. According to CME, these expire on the Friday which precedes, by at
+    least 2 business days, the last business day of the month.
+
+    :param day: the date to check, defaults to today
+
+    :return: the associated monthly
+    """
+    last_day = _get_last_day_of_month(day)
+    first_day = last_day.replace(day=1)
+    valid_range = [d.date() for d in NYSE.valid_days(first_day, last_day)]
+    itr = valid_range[-3]
+    while itr.weekday() != 4:  # Friday
+        itr -= timedelta(days=1)
+    return itr
+
 
 class TastytradeError(Exception):
     """
@@ -30,7 +153,7 @@ class Config:
         allow_population_by_field_name = True
 
 
-def validate_response(response: Response) -> None:  # pragma: no cover
+def validate_response(response: Response) -> None:
     """
     Checks if the given code is an error; if so, raises an exception.
 
diff --git a/tests/test_instruments.py b/tests/test_instruments.py
index 71f48d5..92e7075 100644
--- a/tests/test_instruments.py
+++ b/tests/test_instruments.py
@@ -84,5 +84,5 @@ def test_get_future_option_chain(session):
 
 def test_streamer_symbol_to_occ():
     dxf = '.SPY240324P480.5'
-    occ = 'SPY   20240324P00480500'
+    occ = 'SPY   240324P00480500'
     assert Option.streamer_symbol_to_occ(dxf) == occ
diff --git a/tests/test_utils.py b/tests/test_utils.py
new file mode 100644
index 0000000..5c36b81
--- /dev/null
+++ b/tests/test_utils.py
@@ -0,0 +1,108 @@
+from datetime import date
+
+from tastytrade.utils import (get_future_fx_monthly, get_future_grain_monthly,
+                              get_future_metal_monthly,
+                              get_future_treasury_monthly, get_tasty_monthly,
+                              get_third_friday)
+
+
+def test_get_third_friday():
+    assert get_third_friday(date(2024, 3, 2)) == date(2024, 3, 15)
+
+
+def test_get_tasty_monthly():
+    delta = (get_tasty_monthly() - date.today()).days
+    assert abs(45 - delta) <= 17
+
+
+def test_get_future_fx_monthly():
+    exps = [
+        date(2024, 2, 9),
+        date(2024, 3, 8),
+        date(2024, 4, 5),
+        date(2024, 5, 3),
+        date(2024, 6, 7),
+        date(2024, 7, 5),
+        date(2024, 8, 9),
+        date(2024, 9, 6),
+        date(2024, 10, 4),
+        date(2024, 11, 8),
+        date(2024, 12, 6),
+        date(2025, 1, 3),
+        date(2025, 2, 7),
+        date(2025, 3, 7),
+        date(2025, 6, 6),
+        date(2025, 9, 5),
+        date(2025, 12, 5)
+    ]
+    for exp in exps:
+        assert get_future_fx_monthly(exp) == exp
+
+
+def test_get_future_treasury_monthly():
+    exps = [
+        date(2024, 2, 23),
+        date(2024, 3, 22),
+        date(2024, 4, 26),
+        date(2024, 5, 24),
+        date(2024, 6, 21),
+        date(2024, 8, 23)
+    ]
+    for exp in exps:
+        assert get_future_treasury_monthly(exp) == exp
+
+
+def test_get_future_grain_monthly():
+    exps = [
+        date(2024, 2, 23),
+        date(2024, 3, 22),
+        date(2024, 4, 26),
+        date(2024, 5, 24),
+        date(2024, 6, 21),
+        date(2024, 8, 23),
+        date(2024, 11, 22),
+        date(2025, 2, 21),
+        date(2025, 4, 25),
+        date(2025, 6, 20),
+        date(2025, 11, 21),
+        date(2026, 6, 26),
+        date(2026, 11, 20)
+    ]
+    for exp in exps:
+        assert get_future_grain_monthly(exp) == exp
+
+
+def test_get_future_metal_monthly():
+    exps = [
+        date(2024, 2, 26),
+        date(2024, 3, 25),
+        date(2024, 4, 25),
+        date(2024, 5, 28),
+        date(2024, 6, 25),
+        date(2024, 7, 25),
+        date(2024, 8, 27),
+        date(2024, 9, 25),
+        date(2024, 10, 28),
+        date(2024, 11, 25),
+        date(2024, 12, 26),
+        date(2025, 1, 28),
+        date(2025, 2, 25),
+        date(2025, 3, 26),
+        date(2025, 4, 24),
+        date(2025, 5, 27),
+        date(2025, 6, 25),
+        date(2025, 7, 28),
+        date(2025, 8, 26),
+        date(2025, 9, 25),
+        date(2025, 11, 24),
+        date(2026, 5, 26),
+        date(2026, 11, 24),
+        date(2027, 5, 25),
+        date(2027, 11, 23),
+        date(2028, 5, 25),
+        date(2028, 11, 27),
+        date(2029, 5, 24),
+        date(2029, 11, 27)
+    ]
+    for exp in exps:
+        assert get_future_metal_monthly(exp) == exp