Possible Clues:

• Boston skyscraper, with 'the'
• Boston skyscraper, with "the"
• Boston skyscraper nickname
• Boston landmark, with 'the'
• Newark-based insurer, on the NYSE
• Aetna rival, for short
• Aetna rival, informally
• Moniker for a noted Boston skyscraper, with 'the'
• "Piece of the Rock" company, on the NYSE
• Beantown skyscraper, with "the"