The

First Trust Amex Biotechnology Index

(FBT) - Get Report

ETF was Monday's best performer, rising 3.2% after component

Myogen

( MYOG) agreed to be bought by

Gilead Sciences

(GILD) - Get Report

.

Other biotech-related ETFs were also higher. The

SPDR Biotech

(XBI) - Get Report

ETF was gaining 1.3% to $46.14. The

PowerShares Dynamic Biotech & Genome

(PBE) - Get Report

ETF was adding 1% to $16.91.

However, the

Biotech HOLDRs

(BBH) - Get Report

ETF was lower by nearly 1% as holding Gilead dropped 6.7%.

The

B2B Internet HOLDRs

( BHH) ETF was also stronger as

Ariba

( ARBA) jumped 1.6%. The B2B Internet HOLDRs was gaining 4 cents to $2.27.

ETFs related to housing construction were also rising as the pending home sales index rose 4.3%, according to the National Association of Realtors. Among individual names,

Pulte Homes

(PHM) - Get Report

rose 2.1%,

Centex

(CTX)

was up 1.7%, and

Lennar

(LEN) - Get Report

was tacking on 1%.

The

SPDR Homebuilders

(XHB) - Get Report

ETF was higher by 46 cents, or 1.4%, to $33.18. The

iShares Dow Jones U.S. Home Construction

(ITB) - Get Report

ETF was adding 32 cents, or 0.9%, $37.32.

Among losers, the

Software HOLDRs

(SWH)

ETF was slumping 1%. Holdings

BMC Software

(BMC)

,

Check Point Software

(CHKP) - Get Report

, and

Symantec

(SYMC) - Get Report

were all falling by 2.7%. The Software HOLDRs was off 35 cents to $38.34.

The

iShares Dow Jones U.S. Brokers & Dealers

(FBT) - Get Report

ETF was also lower as holding

Chicago Mercantile Exchange Holdings

(CME) - Get Report

slipped 2.7%. The ETF was down 39 cents, or 0.8%, to $48.98.