What is the fine-grained topic of the following text: Tax Efficiency Core Bond Fund received the following Tax Efficiency ratings for the 3-, 5-, and 10-year periods, respectively: 4 (447 funds), 4 (380 funds), and 3 (293 funds).&lt;br /&gt;&lt;br /&gt;Lipper ratings for Tax Efficiency (US) reflect funds&#39; historical success in postponing taxable distributions relative to peers. Only return the topic.
Tax Efficiency Ratings of Core Bond Fund