diff --git a/piker/exchange/__init__.py b/piker/exchange/__init__.py
new file mode 100644
index 00000000..c4fc2647
--- /dev/null
+++ b/piker/exchange/__init__.py
@@ -0,0 +1,20 @@
+# piker: trading gear for hackers
+# Copyright (C) Tyler Goodlet (in stewardship for piker0)
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+"""
+Market machinery for order executions, book, management.
+
+"""
diff --git a/piker/_ems.py b/piker/exchange/_ems.py
similarity index 99%
rename from piker/_ems.py
rename to piker/exchange/_ems.py
index a0428e26..f594b4ac 100644
--- a/piker/_ems.py
+++ b/piker/exchange/_ems.py
@@ -33,10 +33,10 @@ import trio
 from trio_typing import TaskStatus
 import tractor
 
-from . import data
-from .log import get_logger
-from .data._source import Symbol
-from .data._normalize import iterticks
+from .. import data
+from ..log import get_logger
+from ..data._source import Symbol
+from ..data._normalize import iterticks
 
 
 log = get_logger(__name__)
diff --git a/piker/ui/_chart.py b/piker/ui/_chart.py
index b89eede9..f11ad0f0 100644
--- a/piker/ui/_chart.py
+++ b/piker/ui/_chart.py
@@ -62,7 +62,7 @@ from ..log import get_logger
 from ._exec import run_qtractor, current_screen
 from ._interaction import ChartView, open_order_mode
 from .. import fsp
-from .._ems import open_ems
+from ..exchange._ems import open_ems
 
 
 log = get_logger(__name__)
diff --git a/piker/ui/_interaction.py b/piker/ui/_interaction.py
index 696f24b3..4f6ee19e 100644
--- a/piker/ui/_interaction.py
+++ b/piker/ui/_interaction.py
@@ -33,7 +33,7 @@ import numpy as np
 from ..log import get_logger
 from ._style import _min_points_to_show, hcolor, _font
 from ._graphics._lines import order_line, LevelLine
-from .._ems import OrderBook
+from ..exchange._ems import OrderBook
 from ..data._source import Symbol
 
 
diff --git a/piker/ui/cli.py b/piker/ui/cli.py
index 1dfea298..78100523 100644
--- a/piker/ui/cli.py
+++ b/piker/ui/cli.py
@@ -149,6 +149,6 @@ def chart(config, symbol, profile):
         tractor_kwargs={
             'debug_mode': True,
             'loglevel': tractorloglevel,
-            'rpc_module_paths': ['piker._ems'],
+            'enable_modules': ['piker.exchange._ems'],
         },
     )