FRANKFURT, May 20 (Reuters) - The European Central Bank announced the following results for its latest liquidity providing operation: Main Refinancing Operation-Allotment Intended Volume: Reference Number: 20140109 Min Allotment: Transaction Type: Reverse Transactions Fixed Rate: 0.25 % Operation Type: Liquidity Providing Max Bid Limit: Procedure: Standard Tender Max Bids per Cpty: 1 Tender Date: 20/05/2014 11:15 Marg. Rate: Start Date: 21/05/2014 % of All. at Fixed Rate: 100 Maturity Date: 28/05/2014 Tot Amount Allotted: 131956.7 mn Duration (days): 7 Weight. Avg. Allot. Rate: Tot Bid Amount: 131956.7 mn Auction Type: Fixed Rate Tender Tot Number of Bidders: 193 Allotment Method: Min Rate (bids): Max Rate (bids): Estimate on 20/05/2014 of the average autonomous factors for the period 19/05/2014 to 27/05/2014 amounts to EUR 523.0 bn. Benchmark allotment based on the ECB's liquidity forecast as of 20/05/2014 amounts to EUR 148.0 bn. For general information on the calculation of the benchmark allotment amount, please see www.ecb.europa.eu/mopo/liq/html/index.en.html as well as ECB page Operational Communications.