From the Collaborative Bond and Money Market Data Portal.
Repo is the sale and repurchase of a debt instrument for typically a short period of time. It is like a collateral form of financing where the debt instrument sold and repurchased acts as the underlying asset thereby reducing the credit risk of the short term loan. In particular where the instrument is a government bond, it will typically be cheaper then borrowing outright. Most repo transactions happens overnight providing dealers with essential liquidity to fund their trading positions. Repo therefore performs an essential role in creating liquid financial markets.
Reverse Repo is the transaction on the other side. It is the buying and the pre-agreed selling of a debt instrument at some future point in time. Whilst this is the standard definition, funds will typically report these positions as Repo or USRepo.
In the Collaborative Bond and Money Market Data Model the Repo classification appears within the field Security Type.
Based on available data, the European Repo market measures some EUR5,608bn of which during 2015 US domestic and International Money Market Funds reported holding a total of USD600bn-750bn in oustanding repo transactions.
For information on the Repo Market, please use the data sheet tool. Select Instrument Type as Repo and USRepo and report type "By Fund".