SAN FRANCISCO -- Chipmakers can do no right. While tech results in general have been shining bright this earnings season, the semiconductor companies are taking a drubbing. From Altera ( ALTR) to SanDisk ( SNDK), chipmakers of all stripes are experiencing double-digit percentage declines in their share prices after reporting their quarterly financial results. The carnage accelerated on Wednesday, as The Philadelphia Stock Exchange Semiconductor Sector Index tumbled 5% to its lowest level since mid-January. That downturn didn't help the broader Nasdaq index, which had shed 2.5%, almost mirroring Friday's big selloff. "The market kind of wants to whack the semis right now," says Mike Binger, a fund manager at Thrivent Investment management, which owns shares in various chip firms. Macroeconomic concerns about a slowing economy are obviously hanging over the chip sector -- which is vulnerable to a slowdown in consumer and business spending on technology. But these fears don't appear to be affecting many in the broader tech sector, where companies like Apple ( AAPL), Seagate ( STX) and Google ( GOOG) have seen their shares rise after releasing financial results. And the chip selloff comes at a time when the PC market -- which accounts for 40% of semiconductor sales -- is proving to be healthier than expected . Industry research firm IDC said third-quarter PC shipments increased 15.5% year over year, and microprocessor shipments jumped 14.3%. Recent worries that "double-ordering" by chip customers was creating an inventory glut have been refuted by various companies.