FORTUNE — Steve Ballmer today began his farewell tour, announcing that next September he will step down as CEO of Microsoft after more than 13 years in the position.

To be sure, it has not been a smooth tenure. But today I’ve seen some potshots at Ballmer related to the company’s market cap. And I think it’s largely unfair.

Yes, Microsoft was valued at around $601 billion when Ballmer took over in early 2000, compared to the $270 billion it was at before the news broke of his pending retirement (it’s since gained about $20 billion or so). And yes, it has been lapped by such companies as Apple AAPL and Google GOOG .

But look at what’s happened to the other companies in the top 10 for market cap when Ballmer was named CEO:

1. Microsoft MSFT :
Then: $601 billion
Now: $270 billion

Change: -55%

2. General Electric GE
Then: $492 billion
Now: $242 billion
Change: -50.81%

3. Cisco Systems CSCO
Then: $370 billion
Now: $128.5 billion
Change:
-65%

4. Wal-Mart Stores WMT
Then: $289 billion
Now: $241 billion
Change: -16.6%

5. Intel Corp. INTC
Then: $291 billion
Now: $112 billion
Change: -61.5%

6. Exxon Mobil  XOM
Then: $271 billion
Now: $385.5 billion
Change: +42.25%

7. International Business Machines IBM
Then: $208 billion
Now: $203 billion
Change: -2.4%

8. Time Warner Inc. TWX
Then: $185 billion
Now: $57 billion
Change: -69%

9. Citigroup C
Then: $178 billion
Now: $151 billion
Change: -15.17%

10. Oracle Corp. ORCL
Then: $167 billion
Now: $147 billion
Change:
-11.97%

Outside of Exxon Mobil, every single other company in the Top 10 from January 2000 is worth less today than it was then. And most by double digits — three of which had worse percentage losses than Microsoft did.

And this doesn’t even touch on a series of other tech companies that were a bit lower down the market cap list in January 2000, including Dell DELL and Yahoo YHOO , which also lost more market cap than did Microsoft on a percentage basis.

Again, I’m not saying Ballmer was a rock star. The company did lose stock market value, tech market share and all cache all over the place.

RELATED: The $16 billion drag on Microsoft

But it is worth remembering that he took over the world’s most valuable company in the midst of an economic bubble driven by that company’s industry. The fall was steep, but that was partially because Microsoft began from the highest branch. Ballmer’s legacy — for better or for worse — should not be predicated on the irrational exuberance of January 2000.

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