DexCom (DXCM) - Get Report shares fell Tuesday after rival Tandem Diabetes Care (TNDM) - Get Report  said it was partnering with Abbott Labs (ABT) - Get Report to develop a new insulin pump featuring Abbott's glucose-sensing technology.

Tandem and Abbott "can provide new ways for people to manage their diabetes" that "can integrate easily into their daily lives, especially people who rely on insulin pumps," Abbott Vice President Jared Watkin said in a statement. 

The partnership ends exclusivity for DexCom in the space and exposes 15% of the company's sales to competition, according to Bloomberg. 

Meanwhile, Abbott Labs shares advanced nearly 3% Tuesday after the company announced a $3 billion share repurchase program to be added to the $795 million remaining from a previous buyback plan. 

Abbott is scheduled to report third-quarter earnings on Wednesday before the market opens.

DexCom shares closed down 4.5% to $152.97. Tandem shares were up 9.5% to $61.99. Abbott shares rose 2.7% to $81.98. 

Abbott Labs is a key holding in Jim Cramer's Action Alerts PLUS charitable trust