Oct 22 (Reuters) - Investors ramped up purchases in U.S. equity funds in the week to Oct. 20, as investors eyed better than expected third-quarter earnings from U.S. companies. Investors bought a net $4.78 billion in U.S. equity funds in the week, marking the largest weekly net purchase since mid-September, Lipper data showed. Refinitiv data shows 77% of U.S. companies have so far topped their consensus net income estimates for the third quarter. Companies also posted solid earnings margins, which relieved some fears over rising costs and inflation. Among sector funds, tech funds drew their biggest weekly inflow in three months, worth a net $1.37 billion, financials attracted $1.06 billion, and consumer discretionary and materials both received over $300 million. U.S. bond funds received $6.5 billion, their biggest inflow in seven weeks. U.S. taxable bond funds received a net $6.42 billion, their biggest weekly inflow since the week to Sept. 1, though U.S. municipal debt funds faced outflows of about $14 million. U.S. general domestic taxable fixed income funds secured a net $2.35 billion, their largest weekly inflow in 2-1/2 months, while U.S. short/intermediate investment-grade funds attracted $1.72 billion. Meanwhile, U.S. money market funds saw a fourth straight week of outflow, worth a net $4.41 billion. Reporting by Gaurav Dogra and Patturaja Murugaboopathy in Bengaluru;