FRANKFURT, May 21 (Reuters) - The European Central Bank announced the following results for its latest liquidity providing operation: Main Refinancing Operation-Allotment Intended Volume: Reference Number: 20130105 Min Allotment: Transaction Type: Reverse Transactions Fixed Rate: 0.50 % Operation Type: Liquidity Providing Max Bid Limit: Procedure: Standard Tender Max Bids per Cpty: 1 Tender Date: 21/05/2013 11:15 Marg. Rate: Start Date: 22/05/2013 % of All. at Fixed Rate: 100 Maturity Date: 29/05/2013 Tot Amount Allotted: 103399.2 mn Duration (days): 7 Weight. Avg. Allot. Rate: Tot Bid Amount: 103399.2 mn Auction Type: Fixed Rate Tender Tot Number of Bidders: 62 Allotment Method: Min Rate (bids): Max Rate (bids): Estimate on 21/05/13 of the average autonomous factors for the period 20/05/13 to 28/05/13 amounts to 513.9 EUR bn. Benchmark allotment based on the ECB's liquidity forecasts as at 21/05/13 amounts to EUR 36.5 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.