The healthcare sector and its related exchange traded funds are not strangers to mergers and acquisitions activity. Arguably, the sector can be called an epicenter for this year’s spate of deal-making.

ETF investors can choose from a variety of funds littered with potential suitors and targets. That sentiment is true of healthcare industry funds as well, including the $837 million iShares U.S. Healthcare Providers ETF (NYSEArca: IHF), one of this year’s best-performing health care ETFs.

“Consolidation remains likely, with CEO Mark Bertolini asserting that government business is the focus for inorganic growth, while compatible cultures for post-merger synergies were viewed as the driver in all transactions, with cheap debt making either Aetna-Humana and Aetna-Cigna meaningfully accretive possibilities and imminent,” according to a Leerink note posted by Ben Levisohn of Barron’s.

Aetna is IHF’s fourth-largest holding at a weight of 6.85% while Cigna (NYSE: CI) and Humana are the ETF’s fifth- and seventh-largest holdings, respectively, combining for over 11% of IHF’s weight, according to iShares data.

IHF is no stranger to consolidation in the healthcare services and providers industry. At the end of the first quarter, Dow component UnitedHealth (NYSE: UNH), IHF’s largest holding at a weight of 13.8%, agreed to acquire Catamaran for $12.8 billion in cash.

In 2009, Express Scripts (NasdaqGM: ESRX) spent $4.7 billion to acquire WellPoint and followed up that deal with the $29 billion acquisition of Medco in 2012. [Healthcare ETFs Remain Sturdy]

Last year, Morgan Stanley identified Express Scripts, Cigna and Aetna as possible takeover targets. Investors like the IHF story. A year ago, IHF had about $400 million in assets under management, meaning the ETF’s AUM total has more than doubled in a year. [Obamacare ETF Keeps Rising]

More Americans are enrolling into healthcare plans under the new Patient Protection and Affordable Care Act, or the so-called Obamacare Act, the 2010 law that requires all Americans to hold health insurance, further bolstering the case for IHF and its constituents.

iShares U.S. Healthcare Providers ETF