It hasn’t been a good start to February for crude prices, especially in recent days.

Weighed down by a resurgent US dollar, concerns about a ramping up in US shale production and massive build in US crude inventories reported by the American Petroleum Institute (API) on Tuesday, front-month WTI futures have been hammered, falling to the lowest level seen since January 20.

From the high of $54.34 per barrel on February 2, it’s now lost close to 5%.

Front-Month WTI Futures Hourly Chart. Thomson Reuters via Business Insider Australia

After being undermined by a rebound in the US dollar and intensified concerns over a rebound in US shale oil production, the latest leg lower was sparked by a mammoth build in US crude inventories last week.

The API reported that inventories increased by a massive 14.227 million barrels — one of the largest weekly builds on record — which was significantly higher than the build of 2.38 million expected by markets.

The enormous build comes just a day before the release of separate data from the US Energy Information Administration (EIA) on inventory levels on Wednesday.

If the API data is confirmed by the EIA, it will be the largest build since October last year, according to Reuters.

Front-month WTI futures currently trade at $51.70 a barrel.