The Dow Jones Industrial Average (DJINDICES:^DJI) was up more than 52 points as of 11:30 a.m. EST, but a few tech stocks were outperforming the index. Dow component Intel (NASDAQ:INTC) was having a great session, rising more than 0.50%, while Twitter (NYSE:TWTR) was up better than 6% and Marvell Technology (NASDAQ:MRVL) rallied more than 5%.

Chicago PMI falls short of expectations
The Chicago Purchasing Managers' Index (PMI) came in short of expectations: a reading of 59.1 was worse than the 61 economists had anticipated. The report is a measure of manufacturing economy in the Chicago region; any reading more than 50 indicates expansion, while a reading under 50 shows contraction.

The 59.1 figure suggests that the manufacturing economy, at least in the Chicago region, is strengthening, yet still not strengthening as much as economists had expected. Nevertheless, investors didn't seem to be putting too much stock in the number early on Tuesday.

Intel revenue could come in strong
Intel jumped early on Tuesday after a note from analysts at Maxim Group painted a positive picture of the chip maker. According to Maxim, Intel's fourth-quarter revenue should come in at the upper end of its guidance range when it next reports earnings. Intel has said it expected revenue of $13.2 billion-$14.2 billion.

Maxim Group cited an improving market for traditional PCs, both among businesses and consumers. Although Intel has begun to branch out into mobile, it is still largely dependent on the market for traditional PCs, making the processors that power the vast majority of the computers.

Twitter bounces back after multisession beat-down
Social media giant Twitter continues its post-IPO roller-coaster ride. The Tuesday stock surge occurred despite a lack of any positive news. Investors may have simply been bidding up the stock in the wake of a recent, relatively severe, sell-off.

Shares of Twitter plunged on Friday and again on Monday after a downgrade at Macquarie sparked concerns about the stock's valuation. Last week, trading near $74, Twitter had nearly tripled from its IPO price of $26 per share. Even with Tuesday's rally, Twitter is far removed from its high, but is still up better than 100% from its IPO price.

KKR plans Marvell shakeup
Unlike Twitter, there was reason for Marvell Technology's upward move -- in a regulatory filing, KKR disclosed that it had acquired 6.8% of the chip maker.

That alone would normally be enough to prompt a rally, but KKR's purchase was all the more noteworthy because of what it said it planned to do. In addition to disclosing its stake, KKR said it may engage Marvell's management, possibly pushing for a merger or reorganization of the company. Such a radical transaction could result in a lot of additional shareholder value.