Place the beef tenderloin on a baking sheet and pat dry with paper towels. Spread the olive oil over the entire surface of the tenderloin and sprinkle evenly with salt and pepper.
Heat a roasting pan over high heat and add the tenderloin to the pan. Sear the beef on all sides until a golden brown crust has formed, approximately 10 minutes.
Transfer the roasting pan to the oven and roast the beef for 20 minutes. (for medium-rare)
Remove the beef from the oven and cover with foil. Allow to rest for 15 minutes.
While the beef is resting, make the sauce by whisking together the sour cream, horseradish, dijon, vinegar, worcestershire sauce, salt, pepper and chives.
Beef tenderloin can be served warm or at room temperature. Best if served the same day. The sauce can be made up to 2 days in advance and stored in the refrigerator in an airtight container.