The following businesses are the top taxpayers in town, according to Windsor's grand list, which is accurate as of October 2011:
- Walgreens Eastern - makes up just over 5 percent of the town's grand list with an assets value of $151,368,375.
- Griffin Land & Affiliates - accounts for 2.59 percent of the grand list with assets valued at just over $77 million.
- Hartford Financial Corp. - with assets valued at about $76.5 million, the insurance firm accounts for about 2.5 percent of the entire grand list.
- ING - makes up 2.2 percent of the grand list with an asset value of $68.2 million.
- CIGNA - with a total asset value of $58.7 million, the company makes up just under 2 percent of the grand list.
- IBM & Affiliates - the company makes up about 1.5 percent of the grand list with a total asset value of $46.8 million, which is all personal propery.
- Northeast Utilities & Affiliates - with a total asset value of $42.7 million, the utility accounts for 1.4 percent of the grand list.
- Cellco/Verizon Wireless - making up 1.4 percent of the grand list, the company has a total asset value of $41.7 million.
- Ferraina & Affiliates - the company makes up just under 1 percent of the grand list with a total asset value of $25.9 million.
- GPT Windsor LLC/Rivers Bend Condos - making up .8 percent of the grand list, the company's total asset value is $25,689,650.