* U.S. inflation rise slows in July * U.S. 10-year inflation breakeven rate up slightly * U.S. yield curve flattens after steepening for 4 straight days * U.S. 10-year note auction shows strong results (Adds new comment, updates prices) By Gertrude Chavez-Dreyfuss NEW YORK, Aug 11 (Reuters) - U.S. Treasury yields fell across most maturities on Wednesday in choppy trading, after a strong 10-year note auction and data showing a slight moderation in consumer prices for the month of July in the world"s largest economy. U.S. yields were mixed overall, with those on the long end slightly higher on the day. U.S. 10-year yields dropped to session lows after the auction, falling from four-week peaks earlier in the session. The 10-year note picked up a high yield of 1.34%, much lower than the expected or when-issued rate of 1.375% at the bid deadline, suggesting investors were willing to buy the note at a much lower yield. The bid-to-cover ratio, a gauge of demand, was 2.65, compared with what analysts said was an average of 2.47. The robust 10-year note followed an equally solid U.S. 3-year note sale that was boosted by the recent decline in bond prices and persistent safe-haven demand amid the surge in global virus cases. "The offering was supported by the slowing in July CPI (consumer price index) data, as well as, from some recent cheapening outright with the yield rising for six straight sessions," Kim Rupert, managing director, global fixed income analysis at Action Economics, wrote in a blog after the auction. Wednesday"s data showed U.S. consumer price increases slowed in July, but inflation overall remained historically high. The consumer price index increased 0.5% last month after climbing 0.9% in June. Excluding the volatile food and energy components, the CPI rose 0.3% after increasing 0.9% in June. "A well-behaved CPI print arrived in timely fashion this morning to generate a buying burst not seen since July 30," Jim Vogel, senior rates strategist at FHN Financial, said in a research note. The yield curve, a gauge of economic sentiment and rate move expectations, flattened to 110.40 basis points, as measured by the spread between 2-year and 10-year yields. That curve had steepened in the four previous sessions. U.S. yields were a lot higher before the inflation data, bolstered by comments from two Federal Reserve officials on Tuesday, suggesting that the central bank could soon reduce or taper its asset purchases. Tapering tends to push Treasury debt prices lower and yields higher because it means the Fed is buying less of those bonds. In late afternoon trading, the yield on 10-year Treasury notes was down 1.5 basis points at 1.327%. Earlier in the session, the 10-year yield hit a four-week high of 1.378% The yield on the 30-year Treasury bond was up 1 basis point at 1.994%. The 2-year U.S. Treasury yield, was down 1.7 basis points at 0.221%. The 10-year TIPS breakeven rate, the inflation average expected per year for the next decade, was at 2.402%, slightly up from 2.391% on Tuesday. Also on Wednesday, Dallas Fed President Robert Kaplan, who is currently not a voting member of the Fed policy committee, said the U.S. central bank should announce its timeline on starting the reduction of its massive bond holdings next month, and start tapering in October. August 11 Wednesday 3:44PM New York/1944 GMT Price Current Net Yield % Change (bps) Three-month bills 0.055 0.0558 0.000 Six-month bills 0.0525 0.0532 -0.003 Two-year note 99-208/256 0.2206 -0.017 Three-year note 99-200/256 0.4485 -0.026 Five-year note 99-36/256 0.8018 -0.021 Seven-year note 99-72/256 1.1075 -0.016 10-year note 102-188/256 1.3253 -0.017 20-year bond 105-200/256 1.8977 0.005 30-year bond 108-144/256 1.9921 0.008 DOLLAR SWAP SPREADS Last (bps) Net Change (bps) U.S. 2-year dollar swap 8.00 -0.50 spread U.S. 3-year dollar swap 8.75 -2.50 spread U.S. 5-year dollar swap 8.25 -0.25 spread U.S. 10-year dollar swap 1.00 0.00 spread U.S. 30-year dollar swap -29.50 -0.25 spread (Reporting by Gertrude Chavez-Dreyfuss; Additional reporting by Karen Brettell in New York; Editing by David Evans, Elaine Hardcastle) Our Standards: The Thomson Reuters Trust Principles.