diff --git a/beanprice/sources/csif.py b/beanprice/sources/csif.py
new file mode 100644
index 0000000..7946e65
--- /dev/null
+++ b/beanprice/sources/csif.py
@@ -0,0 +1,133 @@
+"""A source fetching prices and exchangerates from https://amfunds.credit-suisse.com
+
+Valid tickers for prices are in the form "IBAN", such as "CH0031341875".
+
+Here is the API documentation:
+https://www.alphavantage.co/documentation/
+
+Example:
+    https://amfunds.credit-suisse.com/ch/de/institutional/fund/history/CH0031341875
+
+Based on: https://github.com/buchen/portfolio/blob/effa5b7baf9a918e1b5fe83942ddc480e0fd48b9/name.abuchen.portfolio/src/name/abuchen/portfolio/online/impl/CSQuoteFeed.java
+
+"""
+
+from decimal import Decimal
+from typing import Optional
+from dateutil.tz import tz
+from dateutil.parser import parse
+import logging
+import subprocess
+from beanprice import source
+from pathlib import Path
+
+
+class CsifApiError(ValueError):
+    """An error from the CSIF API."""
+
+
+def _fetch_response(ticker):
+    # Download file, or was it cached?
+    filename = '/tmp/beanprice_csif_{}.html'.format(ticker)
+    path = Path(filename)
+    if not path.is_file():
+        logging.debug('Fetching data from server for ticker {}'.format(ticker))
+        # Fetch the HTML workbook, we have to use curl, see PortfolioPerformance documentation
+        link = 'https://amfunds.credit-suisse.com/ch/de/institutional/fund/history/{}?currency=CHF'.format(ticker)
+        try:
+            response = subprocess.check_output(['curl', '-s', link]).decode("utf-8")
+        except BaseException as e:
+            raise CsifApiError('Error connecting to server on URL {}'.format(link))
+
+        # Save to file for future access
+        with open(path, "w") as text_file:
+            text_file.write(response)
+    else:
+        # Read the response from text file
+        logging.debug('Retrieving cached data for ticker {}'.format(ticker))
+        with open(path, "r") as text_file:
+            response = text_file.read()
+
+    # Find first occurrence of HTML tag "<td>IBAN</td>"
+    pos = response.find('<td>{}</td>'.format(ticker))
+    if pos < 0:
+        raise CsifApiError('Ticker {} not fund'.format(ticker))
+    pos = pos + 4
+
+    # Next occurrence of "<td>": security number
+    pos = pos + response[pos:].find('<td>') + 4
+    end_pos = pos + response[pos:].find('</td>')
+    sec_number = response[pos:end_pos]
+
+    # Next occurrence of "<td>": currency
+    pos = pos + response[pos:].find('<td>') + 4
+    end_pos = pos + response[pos:].find('</td>')
+    currency = response[pos:end_pos]
+    logging.debug('Ticker {} data loaded: sec. number {}, currency {}'.format(
+        ticker,
+        sec_number,
+        currency
+    ))
+
+    return response, currency, sec_number
+
+
+class Source(source.Source):
+
+    def get_latest_price(self, ticker) -> Optional[source.SourcePrice]:
+        # Fetch data
+        response, currency, sec_number = _fetch_response(ticker)
+
+        # Find first occurrence of security number
+        pos = response.find('<td>{}</td>'.format(sec_number))
+        if pos < 0:
+            return None
+        pos = pos + 4
+
+        # Next two occurrences of HTML tags "<td>" and "</td>"
+        pos = pos + response[pos:].find('<td>') + 4
+        pos = pos + response[pos:].find('<td>') + 4
+        end_pos = pos + response[pos:].find('</td>')
+
+        # Parse date
+        date_str = response[pos:end_pos]
+        logging.debug('Date: {}'.format(date_str))
+        date = parse(date_str).replace(tzinfo=tz.gettz('Europe/Zurich'))
+
+        # Next occurrence of HTML tags "<td>" and "</td>"
+        pos = pos + response[pos:].find('<td>') + 4
+        end_pos = pos + response[pos:].find('</td>')
+
+        # Parse value
+        logging.debug('Price: {}'.format(response[pos:end_pos]))
+        price = Decimal(response[pos:end_pos])
+
+        logging.debug('Latest price: {} {}, {}'.format(price, currency, date_str))
+        return source.SourcePrice(price, date, currency)
+
+    def get_historical_price(self, ticker, time) -> Optional[source.SourcePrice]:
+        # Fetch data
+        response, currency, sec_number = _fetch_response(ticker)
+
+        # Find relevant date
+        date_str = time.strftime("%d.%m.%Y")
+        pos = response.find(date_str)
+
+        # Found?
+        if pos < 0:
+            # It can happen that a date is missing
+            raise source.MissingDate
+        pos = pos + 10
+
+        # Next occurrences of HTML tags "<td>" and "</td>"
+        pos = pos + response[pos:].find('<td>') + 4
+        end_pos = pos + response[pos:].find('</td>')
+
+        # Parse value
+        try:
+            price = Decimal(response[pos:end_pos])
+        except BaseException as e:
+            raise CsifApiError('Error parsing price {} for date {}'.format(response[pos:end_pos], date_str))
+
+        logging.debug('Historical price: {} {}, {}'.format(price, currency, date_str))
+        return source.SourcePrice(price, time, currency)