INDIANAPOLIS - Indianapolis-based Sigstr Inc. has secured $5 million in funding. The email signature marketing platform says the money will support product development and hiring. The funding came from organizations including Hyde Park Venture Partners and High Alpha Capital.

Sigstr's platform aims to use employee email signatures as a marketing channel. The company says it recently attracted its 300th customer, topped 500 million signature impressions and grew its team to more than 30 employees. Its customers include Indianapolis-based Angie's List Inc. (Nasdaq: ANGI), California Closets and United Way.

The company says the funding will allow it to grow its product, sales and marketing teams.

Last year, Sigstr announced plans to invest nearly $1.5 million to double its downtown Indianapolis footprint and add up to 111 jobs. The company was the first to launch from the High Alpha venture studio.

Tim Kopp, partner with Hyde Park Venture Partners, calls employee email "the last marketing channel that has gone untapped," adding "work email is the first thing you look at when you wake up in the morning and the last thing you check before you go to bed."