An interesting problem from StackOverflow: How to preserve the special character in a token, while also tokenizing the individual special characters. Example: "H&R Blocks tokenized as: "H", "R", "H&R", "Blocks" With the help of this blogpost, a possible solution:

elasticsearchShingleFilterMapping.sh

"settings" : { 
   "analysis" : {
       "filter" : {
           "blocks_filter" : {
               "type" : "word_delimiter",
               "preserve_original": "true"
           },
          "shingle":{
              "type":"shingle",
              "max_shingle_size":5,
              "min_shingle_size":2,
              "output_unigrams":"true"
           },
           "filter_stop":{
              "type":"stop",
              "enable_position_increments":"false"
           }
       },
       "analyzer" : {
           "blocks_analyzer" : {
               "type" : "custom",
               "tokenizer" : "whitespace",
               "filter" : ["lowercase", "blocks_filter", "shingle"]
           }
       }
   }
},
"mappings" : {
   "type" : {
       "properties" : {
           "company" : {
               "type" : "string",
               "analyzer" : "blocks_analyzer"
           }
       }
   }
}